From f328f0c93fcd40b04f1cbddbd32d57a286349f69 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Sun, 21 Jul 2024 16:52:18 -0600
Subject: [PATCH 01/33] Initial commit.

---
 UnitTests/Views/OverlappedTests.cs | 187 ++++++++++++++++++++++++++++
 UnitTests/Views/ToplevelTests.cs   | 189 +----------------------------
 2 files changed, 188 insertions(+), 188 deletions(-)

diff --git a/UnitTests/Views/OverlappedTests.cs b/UnitTests/Views/OverlappedTests.cs
index b4437b89d..9c7202d68 100644
--- a/UnitTests/Views/OverlappedTests.cs
+++ b/UnitTests/Views/OverlappedTests.cs
@@ -1015,4 +1015,191 @@ public class OverlappedTests
     {
         public Overlapped () { IsOverlappedContainer = true; }
     }
+
+    [Fact]
+    [AutoInitShutdown]
+    public void KeyBindings_Command_With_OverlappedTop ()
+    {
+        Toplevel top = new ();
+        Assert.Null (Application.OverlappedTop);
+        top.IsOverlappedContainer = true;
+        Application.Begin (top);
+        Assert.Equal (Application.Top, Application.OverlappedTop);
+
+        var isRunning = true;
+
+        var win1 = new Window { Id = "win1", Width = Dim.Percent (50), Height = Dim.Fill () };
+        var lblTf1W1 = new Label { Text = "Enter text in TextField on Win1:" };
+        var tf1W1 = new TextField { X = Pos.Right (lblTf1W1) + 1, Width = Dim.Fill (), Text = "Text1 on Win1" };
+        var lblTvW1 = new Label { Y = Pos.Bottom (lblTf1W1) + 1, Text = "Enter text in TextView on Win1:" };
+
+        var tvW1 = new TextView
+        {
+            X = Pos.Left (tf1W1), Width = Dim.Fill (), Height = 2, Text = "First line Win1\nSecond line Win1"
+        };
+        var lblTf2W1 = new Label { Y = Pos.Bottom (lblTvW1) + 1, Text = "Enter text in TextField on Win1:" };
+        var tf2W1 = new TextField { X = Pos.Left (tf1W1), Width = Dim.Fill (), Text = "Text2 on Win1" };
+        win1.Add (lblTf1W1, tf1W1, lblTvW1, tvW1, lblTf2W1, tf2W1);
+
+        var win2 = new Window { Id = "win2", Width = Dim.Percent (50), Height = Dim.Fill () };
+        var lblTf1W2 = new Label { Text = "Enter text in TextField on Win2:" };
+        var tf1W2 = new TextField { X = Pos.Right (lblTf1W2) + 1, Width = Dim.Fill (), Text = "Text1 on Win2" };
+        var lblTvW2 = new Label { Y = Pos.Bottom (lblTf1W2) + 1, Text = "Enter text in TextView on Win2:" };
+
+        var tvW2 = new TextView
+        {
+            X = Pos.Left (tf1W2), Width = Dim.Fill (), Height = 2, Text = "First line Win1\nSecond line Win2"
+        };
+        var lblTf2W2 = new Label { Y = Pos.Bottom (lblTvW2) + 1, Text = "Enter text in TextField on Win2:" };
+        var tf2W2 = new TextField { X = Pos.Left (tf1W2), Width = Dim.Fill (), Text = "Text2 on Win2" };
+        win2.Add (lblTf1W2, tf1W2, lblTvW2, tvW2, lblTf2W2, tf2W2);
+
+        win1.Closing += (s, e) => isRunning = false;
+        Assert.Null (top.Focused);
+        Assert.Equal (top, Application.Current);
+        Assert.True (top.IsCurrentTop);
+        Assert.Equal (top, Application.OverlappedTop);
+        Application.Begin (win1);
+        Assert.Equal (new (0, 0, 40, 25), win1.Frame);
+        Assert.NotEqual (top, Application.Current);
+        Assert.False (top.IsCurrentTop);
+        Assert.Equal (win1, Application.Current);
+        Assert.True (win1.IsCurrentTop);
+        Assert.True (win1.IsOverlapped);
+        Assert.Null (top.Focused);
+        Assert.Null (top.MostFocused);
+        Assert.Equal (tf1W1, win1.MostFocused);
+        Assert.True (win1.IsOverlapped);
+        Assert.Single (Application.OverlappedChildren);
+        Application.Begin (win2);
+        Assert.Equal (new (0, 0, 40, 25), win2.Frame);
+        Assert.NotEqual (top, Application.Current);
+        Assert.False (top.IsCurrentTop);
+        Assert.Equal (win2, Application.Current);
+        Assert.True (win2.IsCurrentTop);
+        Assert.True (win2.IsOverlapped);
+        Assert.Null (top.Focused);
+        Assert.Null (top.MostFocused);
+        Assert.Equal (tf1W2, win2.MostFocused);
+        Assert.Equal (2, Application.OverlappedChildren.Count);
+
+        Application.MoveToOverlappedChild (win1);
+        Assert.Equal (win1, Application.Current);
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        win1.Running = true;
+        Assert.True (Application.OnKeyDown (Application.QuitKey));
+        Assert.False (isRunning);
+        Assert.False (win1.Running);
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+
+        Assert.True (
+                     Application.OnKeyDown (Key.Z.WithCtrl)
+                    );
+
+        Assert.True (Application.OnKeyDown (Key.F5)); // refresh
+
+        Assert.True (Application.OnKeyDown (Key.Tab));
+        Assert.True (win1.IsCurrentTop);
+        Assert.Equal (tvW1, win1.MostFocused);
+        Assert.True (Application.OnKeyDown (Key.Tab));
+        Assert.Equal ($"\tFirst line Win1{Environment.NewLine}Second line Win1", tvW1.Text);
+
+        Assert.True (
+                     Application.OnKeyDown (Key.Tab.WithShift)
+                    );
+        Assert.Equal ($"First line Win1{Environment.NewLine}Second line Win1", tvW1.Text);
+
+        Assert.True (
+                     Application.OnKeyDown (Key.Tab.WithCtrl)
+                    );
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tf2W1, win1.MostFocused);
+        Assert.True (Application.OnKeyDown (Key.Tab));
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tf1W1, win1.MostFocused);
+        Assert.True (Application.OnKeyDown (Key.CursorRight));
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tf1W1, win1.MostFocused);
+        Assert.True (Application.OnKeyDown (Key.CursorDown));
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tvW1, win1.MostFocused);
+#if UNIX_KEY_BINDINGS
+        Assert.True (Application.OverlappedChildren [0].ProcessKeyDown (new (Key.I.WithCtrl)));
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tf2W1, win1.MostFocused);
+#endif
+        Assert.True (
+                     Application.OverlappedChildren [0]
+                                .NewKeyDownEvent (Key.Tab.WithShift)
+                    );
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tvW1, win1.MostFocused);
+        Assert.True (Application.OnKeyDown (Key.CursorLeft));
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tf1W1, win1.MostFocused);
+        Assert.True (Application.OnKeyDown (Key.CursorUp));
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tf2W1, win1.MostFocused);
+        Assert.True (Application.OnKeyDown (Key.Tab));
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tf1W1, win1.MostFocused);
+
+        Assert.True (
+                     Application.OverlappedChildren [0]
+                                .NewKeyDownEvent (Key.Tab.WithCtrl)
+                    );
+        Assert.Equal (win2, Application.OverlappedChildren [0]);
+        Assert.Equal (tf1W2, win2.MostFocused);
+        tf2W2.SetFocus ();
+        Assert.True (tf2W2.HasFocus);
+
+        Assert.True (
+                     Application.OverlappedChildren [0]
+                                .NewKeyDownEvent (Key.Tab.WithCtrl.WithShift)
+                    );
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tf1W1, win1.MostFocused);
+        Assert.True (Application.OnKeyDown (Application.AlternateForwardKey));
+        Assert.Equal (win2, Application.OverlappedChildren [0]);
+        Assert.Equal (tf2W2, win2.MostFocused);
+        Assert.True (Application.OnKeyDown (Application.AlternateBackwardKey));
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tf1W1, win1.MostFocused);
+        Assert.True (Application.OnKeyDown (Key.CursorDown));
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tvW1, win1.MostFocused);
+#if UNIX_KEY_BINDINGS
+        Assert.True (Application.OverlappedChildren [0].ProcessKeyDown (new (Key.B.WithCtrl)));
+#else
+        Assert.True (Application.OnKeyDown (Key.CursorLeft));
+#endif
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tf1W1, win1.MostFocused);
+        Assert.True (Application.OnKeyDown (Key.CursorDown));
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tvW1, win1.MostFocused);
+        Assert.Equal (Point.Empty, tvW1.CursorPosition);
+
+        Assert.True (
+                     Application.OverlappedChildren [0]
+                                .NewKeyDownEvent (Key.End.WithCtrl)
+                    );
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tvW1, win1.MostFocused);
+        Assert.Equal (new (16, 1), tvW1.CursorPosition);
+#if UNIX_KEY_BINDINGS
+        Assert.True (Application.OverlappedChildren [0].ProcessKeyDown (new (Key.F.WithCtrl)));
+#else
+        Assert.True (Application.OnKeyDown (Key.CursorRight));
+#endif
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tf2W1, win1.MostFocused);
+
+#if UNIX_KEY_BINDINGS
+        Assert.True (Application.OverlappedChildren [0].ProcessKeyDown (new (Key.L.WithCtrl)));
+#endif
+        win2.Dispose ();
+        win1.Dispose ();
+        top.Dispose ();
+    }
 }
diff --git a/UnitTests/Views/ToplevelTests.cs b/UnitTests/Views/ToplevelTests.cs
index ed3482a50..abbfdeb59 100644
--- a/UnitTests/Views/ToplevelTests.cs
+++ b/UnitTests/Views/ToplevelTests.cs
@@ -2,7 +2,7 @@
 
 namespace Terminal.Gui.ViewsTests;
 
-public class ToplevelTests (ITestOutputHelper output)
+public partial class ToplevelTests (ITestOutputHelper output)
 {
     [Fact]
     public void Constructor_Default ()
@@ -556,193 +556,6 @@ public class ToplevelTests (ITestOutputHelper output)
         top.Dispose ();
     }
 
-    [Fact]
-    [AutoInitShutdown]
-    public void KeyBindings_Command_With_OverlappedTop ()
-    {
-        Toplevel top = new ();
-        Assert.Null (Application.OverlappedTop);
-        top.IsOverlappedContainer = true;
-        Application.Begin (top);
-        Assert.Equal (Application.Top, Application.OverlappedTop);
-
-        var isRunning = true;
-
-        var win1 = new Window { Id = "win1", Width = Dim.Percent (50), Height = Dim.Fill () };
-        var lblTf1W1 = new Label { Text = "Enter text in TextField on Win1:" };
-        var tf1W1 = new TextField { X = Pos.Right (lblTf1W1) + 1, Width = Dim.Fill (), Text = "Text1 on Win1" };
-        var lblTvW1 = new Label { Y = Pos.Bottom (lblTf1W1) + 1, Text = "Enter text in TextView on Win1:" };
-
-        var tvW1 = new TextView
-        {
-            X = Pos.Left (tf1W1), Width = Dim.Fill (), Height = 2, Text = "First line Win1\nSecond line Win1"
-        };
-        var lblTf2W1 = new Label { Y = Pos.Bottom (lblTvW1) + 1, Text = "Enter text in TextField on Win1:" };
-        var tf2W1 = new TextField { X = Pos.Left (tf1W1), Width = Dim.Fill (), Text = "Text2 on Win1" };
-        win1.Add (lblTf1W1, tf1W1, lblTvW1, tvW1, lblTf2W1, tf2W1);
-
-        var win2 = new Window { Id = "win2", Width = Dim.Percent (50), Height = Dim.Fill () };
-        var lblTf1W2 = new Label { Text = "Enter text in TextField on Win2:" };
-        var tf1W2 = new TextField { X = Pos.Right (lblTf1W2) + 1, Width = Dim.Fill (), Text = "Text1 on Win2" };
-        var lblTvW2 = new Label { Y = Pos.Bottom (lblTf1W2) + 1, Text = "Enter text in TextView on Win2:" };
-
-        var tvW2 = new TextView
-        {
-            X = Pos.Left (tf1W2), Width = Dim.Fill (), Height = 2, Text = "First line Win1\nSecond line Win2"
-        };
-        var lblTf2W2 = new Label { Y = Pos.Bottom (lblTvW2) + 1, Text = "Enter text in TextField on Win2:" };
-        var tf2W2 = new TextField { X = Pos.Left (tf1W2), Width = Dim.Fill (), Text = "Text2 on Win2" };
-        win2.Add (lblTf1W2, tf1W2, lblTvW2, tvW2, lblTf2W2, tf2W2);
-
-        win1.Closing += (s, e) => isRunning = false;
-        Assert.Null (top.Focused);
-        Assert.Equal (top, Application.Current);
-        Assert.True (top.IsCurrentTop);
-        Assert.Equal (top, Application.OverlappedTop);
-        Application.Begin (win1);
-        Assert.Equal (new (0, 0, 40, 25), win1.Frame);
-        Assert.NotEqual (top, Application.Current);
-        Assert.False (top.IsCurrentTop);
-        Assert.Equal (win1, Application.Current);
-        Assert.True (win1.IsCurrentTop);
-        Assert.True (win1.IsOverlapped);
-        Assert.Null (top.Focused);
-        Assert.Null (top.MostFocused);
-        Assert.Equal (tf1W1, win1.MostFocused);
-        Assert.True (win1.IsOverlapped);
-        Assert.Single (Application.OverlappedChildren);
-        Application.Begin (win2);
-        Assert.Equal (new (0, 0, 40, 25), win2.Frame);
-        Assert.NotEqual (top, Application.Current);
-        Assert.False (top.IsCurrentTop);
-        Assert.Equal (win2, Application.Current);
-        Assert.True (win2.IsCurrentTop);
-        Assert.True (win2.IsOverlapped);
-        Assert.Null (top.Focused);
-        Assert.Null (top.MostFocused);
-        Assert.Equal (tf1W2, win2.MostFocused);
-        Assert.Equal (2, Application.OverlappedChildren.Count);
-
-        Application.MoveToOverlappedChild (win1);
-        Assert.Equal (win1, Application.Current);
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        win1.Running = true;
-        Assert.True (Application.OnKeyDown (Application.QuitKey));
-        Assert.False (isRunning);
-        Assert.False (win1.Running);
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-
-        Assert.True (
-                     Application.OnKeyDown (Key.Z.WithCtrl)
-                    );
-
-        Assert.True (Application.OnKeyDown (Key.F5)); // refresh
-
-        Assert.True (Application.OnKeyDown (Key.Tab));
-        Assert.True (win1.IsCurrentTop);
-        Assert.Equal (tvW1, win1.MostFocused);
-        Assert.True (Application.OnKeyDown (Key.Tab));
-        Assert.Equal ($"\tFirst line Win1{Environment.NewLine}Second line Win1", tvW1.Text);
-
-        Assert.True (
-                     Application.OnKeyDown (Key.Tab.WithShift)
-                    );
-        Assert.Equal ($"First line Win1{Environment.NewLine}Second line Win1", tvW1.Text);
-
-        Assert.True (
-                     Application.OnKeyDown (Key.Tab.WithCtrl)
-                    );
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf2W1, win1.MostFocused);
-        Assert.True (Application.OnKeyDown (Key.Tab));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf1W1, win1.MostFocused);
-        Assert.True (Application.OnKeyDown (Key.CursorRight));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf1W1, win1.MostFocused);
-        Assert.True (Application.OnKeyDown (Key.CursorDown));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tvW1, win1.MostFocused);
-#if UNIX_KEY_BINDINGS
-        Assert.True (Application.OverlappedChildren [0].ProcessKeyDown (new (Key.I.WithCtrl)));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf2W1, win1.MostFocused);
-#endif
-        Assert.True (
-                     Application.OverlappedChildren [0]
-                                .NewKeyDownEvent (Key.Tab.WithShift)
-                    );
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tvW1, win1.MostFocused);
-        Assert.True (Application.OnKeyDown (Key.CursorLeft));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf1W1, win1.MostFocused);
-        Assert.True (Application.OnKeyDown (Key.CursorUp));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf2W1, win1.MostFocused);
-        Assert.True (Application.OnKeyDown (Key.Tab));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf1W1, win1.MostFocused);
-
-        Assert.True (
-                     Application.OverlappedChildren [0]
-                                .NewKeyDownEvent (Key.Tab.WithCtrl)
-                    );
-        Assert.Equal (win2, Application.OverlappedChildren [0]);
-        Assert.Equal (tf1W2, win2.MostFocused);
-        tf2W2.SetFocus ();
-        Assert.True (tf2W2.HasFocus);
-
-        Assert.True (
-                     Application.OverlappedChildren [0]
-                                .NewKeyDownEvent (Key.Tab.WithCtrl.WithShift)
-                    );
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf1W1, win1.MostFocused);
-        Assert.True (Application.OnKeyDown (Application.AlternateForwardKey));
-        Assert.Equal (win2, Application.OverlappedChildren [0]);
-        Assert.Equal (tf2W2, win2.MostFocused);
-        Assert.True (Application.OnKeyDown (Application.AlternateBackwardKey));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf1W1, win1.MostFocused);
-        Assert.True (Application.OnKeyDown (Key.CursorDown));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tvW1, win1.MostFocused);
-#if UNIX_KEY_BINDINGS
-        Assert.True (Application.OverlappedChildren [0].ProcessKeyDown (new (Key.B.WithCtrl)));
-#else
-        Assert.True (Application.OnKeyDown (Key.CursorLeft));
-#endif
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf1W1, win1.MostFocused);
-        Assert.True (Application.OnKeyDown (Key.CursorDown));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tvW1, win1.MostFocused);
-        Assert.Equal (Point.Empty, tvW1.CursorPosition);
-
-        Assert.True (
-                     Application.OverlappedChildren [0]
-                                .NewKeyDownEvent (Key.End.WithCtrl)
-                    );
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tvW1, win1.MostFocused);
-        Assert.Equal (new (16, 1), tvW1.CursorPosition);
-#if UNIX_KEY_BINDINGS
-        Assert.True (Application.OverlappedChildren [0].ProcessKeyDown (new (Key.F.WithCtrl)));
-#else
-        Assert.True (Application.OnKeyDown (Key.CursorRight));
-#endif
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf2W1, win1.MostFocused);
-
-#if UNIX_KEY_BINDINGS
-        Assert.True (Application.OverlappedChildren [0].ProcessKeyDown (new (Key.L.WithCtrl)));
-#endif
-        win2.Dispose ();
-        win1.Dispose ();
-        top.Dispose ();
-    }
-
     [Fact]
     public void Added_Event_Should_Not_Be_Used_To_Initialize_Toplevel_Events ()
     {

From 44ce74a5c0e2debadb3771e24ca6452018850771 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Mon, 22 Jul 2024 16:52:02 -0600
Subject: [PATCH 02/33] Refactored Application into smaller files. Made
 Application #nullable enable

---
 .../Application/Application.Driver.cs         |   29 +
 .../Application/Application.Initialization.cs |  209 +++
 ...ionKeyboard.cs => Application.Keyboard.cs} |    2 +-
 ...plicationMouse.cs => Application.Mouse.cs} |    4 +-
 Terminal.Gui/Application/Application.Run.cs   |  863 +++++++++++++
 Terminal.Gui/Application/Application.cs       | 1117 +----------------
 Terminal.Gui/Clipboard/Clipboard.cs           |   33 +-
 Terminal.Gui/Drawing/LineCanvas.cs            |    6 +-
 Terminal.Gui/Drawing/Ruler.cs                 |    8 +-
 Terminal.Gui/Drawing/Thickness.cs             |   14 +-
 .../Text/Autocomplete/AppendAutocomplete.cs   |    4 +-
 .../Text/Autocomplete/PopupAutocomplete.cs    |    6 +-
 Terminal.Gui/View/Layout/Dim.cs               |    4 +-
 Terminal.Gui/View/Layout/DimView.cs           |    4 +-
 Terminal.Gui/View/Layout/Pos.cs               |   12 +-
 Terminal.Gui/View/Layout/PosView.cs           |    4 +-
 Terminal.Gui/View/Layout/ViewLayout.cs        |    4 +-
 Terminal.Gui/View/ViewDrawing.cs              |    8 +-
 Terminal.Gui/Views/GraphView/Annotations.cs   |    6 +-
 Terminal.Gui/Views/GraphView/Axis.cs          |   14 +-
 Terminal.Gui/Views/GraphView/Series.cs        |    4 +-
 Terminal.Gui/Views/Menu/ContextMenu.cs        |    2 +-
 Terminal.Gui/Views/RadioGroup.cs              |   12 +-
 UICatalog/Scenarios/CombiningMarks.cs         |   28 +-
 UICatalog/Scenarios/Images.cs                 |    4 +-
 UICatalog/Scenarios/SendKeys.cs               |    2 +-
 UICatalog/Scenarios/TextEffectsScenario.cs    |    2 +-
 UICatalog/Scenarios/TrueColors.cs             |    4 +-
 UICatalog/Scenarios/VkeyPacketSimulator.cs    |    2 +-
 UICatalog/UICatalog.cs                        |    4 +-
 UnitTests/Application/ApplicationTests.cs     |   14 +-
 UnitTests/Application/CursorTests.cs          |    7 +-
 UnitTests/Clipboard/ClipboardTests.cs         |    4 +-
 UnitTests/ConsoleDrivers/ClipRegionTests.cs   |    8 +-
 .../ConsoleDrivers/ConsoleDriverTests.cs      |    2 +-
 .../ConsoleDrivers/ConsoleKeyMappingTests.cs  |    2 +-
 UnitTests/Dialogs/MessageBoxTests.cs          |   20 +-
 UnitTests/Drawing/RulerTests.cs               |   10 +-
 UnitTests/Drawing/ThicknessTests.cs           |   20 +-
 UnitTests/FileServices/FileDialogTests.cs     |    4 +-
 UnitTests/Text/TextFormatterTests.cs          |    4 +-
 UnitTests/View/Adornment/BorderTests.cs       |   16 +-
 UnitTests/View/Adornment/MarginTests.cs       |    2 +-
 UnitTests/View/Adornment/PaddingTests.cs      |    2 +-
 UnitTests/View/DrawTests.cs                   |   46 +-
 UnitTests/View/Layout/Dim.FillTests.cs        |    2 +-
 UnitTests/View/Layout/Pos.AnchorEndTests.cs   |    2 +-
 UnitTests/View/Layout/Pos.CenterTests.cs      |    4 +-
 UnitTests/View/Layout/ViewportTests.cs        |    2 +-
 UnitTests/View/NavigationTests.cs             |   14 +-
 UnitTests/View/TextTests.cs                   |   20 +-
 UnitTests/View/ViewTests.cs                   |   30 +-
 UnitTests/Views/AppendAutocompleteTests.cs    |   36 +-
 UnitTests/Views/ButtonTests.cs                |    6 +-
 UnitTests/Views/CheckBoxTests.cs              |    8 +-
 UnitTests/Views/ContextMenuTests.cs           |   18 +-
 UnitTests/Views/FrameViewTests.cs             |    2 +-
 UnitTests/Views/LabelTests.cs                 |   26 +-
 UnitTests/Views/ListViewTests.cs              |    4 +-
 UnitTests/Views/MenuBarTests.cs               |   28 +-
 UnitTests/Views/OverlappedTests.cs            |    2 +-
 UnitTests/Views/RadioGroupTests.cs            |    2 +-
 UnitTests/Views/ScrollBarViewTests.cs         |   12 +-
 UnitTests/Views/ScrollViewTests.cs            |    2 +-
 UnitTests/Views/TableViewTests.cs             |    2 +-
 UnitTests/Views/TextFieldTests.cs             |   14 +-
 UnitTests/Views/TextViewTests.cs              |   18 +-
 UnitTests/Views/ToplevelTests.cs              |   48 +-
 UnitTests/Views/TreeTableSourceTests.cs       |    4 +-
 UnitTests/Views/TreeViewTests.cs              |    2 +-
 UnitTests/Views/WindowTests.cs                |    6 +-
 71 files changed, 1449 insertions(+), 1441 deletions(-)
 create mode 100644 Terminal.Gui/Application/Application.Driver.cs
 create mode 100644 Terminal.Gui/Application/Application.Initialization.cs
 rename Terminal.Gui/Application/{ApplicationKeyboard.cs => Application.Keyboard.cs} (99%)
 rename Terminal.Gui/Application/{ApplicationMouse.cs => Application.Mouse.cs} (98%)
 create mode 100644 Terminal.Gui/Application/Application.Run.cs

diff --git a/Terminal.Gui/Application/Application.Driver.cs b/Terminal.Gui/Application/Application.Driver.cs
new file mode 100644
index 000000000..f15bd8053
--- /dev/null
+++ b/Terminal.Gui/Application/Application.Driver.cs
@@ -0,0 +1,29 @@
+#nullable enable
+namespace Terminal.Gui;
+
+public static partial class Application // Driver abstractions
+{
+    internal static bool _forceFakeConsole;
+
+    /// <summary>Gets the <see cref="ConsoleDriver"/> that has been selected. See also <see cref="ForceDriver"/>.</summary>
+    public static ConsoleDriver? Driver { get; internal set; }
+
+    /// <summary>
+    ///     Gets or sets whether <see cref="Application.Driver"/> will be forced to output only the 16 colors defined in
+    ///     <see cref="ColorName"/>. The default is <see langword="false"/>, meaning 24-bit (TrueColor) colors will be output
+    ///     as long as the selected <see cref="ConsoleDriver"/> supports TrueColor.
+    /// </summary>
+    [SerializableConfigurationProperty (Scope = typeof (SettingsScope))]
+    public static bool Force16Colors { get; set; }
+
+    /// <summary>
+    ///     Forces the use of the specified driver (one of "fake", "ansi", "curses", "net", or "windows"). If not
+    ///     specified, the driver is selected based on the platform.
+    /// </summary>
+    /// <remarks>
+    ///     Note, <see cref="Application.Init(ConsoleDriver, string)"/> will override this configuration setting if called
+    ///     with either `driver` or `driverName` specified.
+    /// </remarks>
+    [SerializableConfigurationProperty (Scope = typeof (SettingsScope))]
+    public static string ForceDriver { get; set; } = string.Empty;
+}
diff --git a/Terminal.Gui/Application/Application.Initialization.cs b/Terminal.Gui/Application/Application.Initialization.cs
new file mode 100644
index 000000000..a971850e3
--- /dev/null
+++ b/Terminal.Gui/Application/Application.Initialization.cs
@@ -0,0 +1,209 @@
+using System.Diagnostics.CodeAnalysis;
+using System.Reflection;
+
+namespace Terminal.Gui;
+
+public static partial class Application // Initialization (Init/Shutdown)
+{
+    /// <summary>Initializes a new instance of <see cref="Terminal.Gui"/> Application.</summary>
+    /// <para>Call this method once per instance (or after <see cref="Shutdown"/> has been called).</para>
+    /// <para>
+    ///     This function loads the right <see cref="ConsoleDriver"/> for the platform, Creates a <see cref="Toplevel"/>. and
+    ///     assigns it to <see cref="Top"/>
+    /// </para>
+    /// <para>
+    ///     <see cref="Shutdown"/> must be called when the application is closing (typically after
+    ///     <see cref="Run{T}"/> has returned) to ensure resources are cleaned up and
+    ///     terminal settings
+    ///     restored.
+    /// </para>
+    /// <para>
+    ///     The <see cref="Run{T}"/> function combines
+    ///     <see cref="Init(Terminal.Gui.ConsoleDriver,string)"/> and <see cref="Run(Toplevel, Func{Exception, bool})"/>
+    ///     into a single
+    ///     call. An application cam use <see cref="Run{T}"/> without explicitly calling
+    ///     <see cref="Init(Terminal.Gui.ConsoleDriver,string)"/>.
+    /// </para>
+    /// <param name="driver">
+    ///     The <see cref="ConsoleDriver"/> to use. If neither <paramref name="driver"/> or
+    ///     <paramref name="driverName"/> are specified the default driver for the platform will be used.
+    /// </param>
+    /// <param name="driverName">
+    ///     The short name (e.g. "net", "windows", "ansi", "fake", or "curses") of the
+    ///     <see cref="ConsoleDriver"/> to use. If neither <paramref name="driver"/> or <paramref name="driverName"/> are
+    ///     specified the default driver for the platform will be used.
+    /// </param>
+    [RequiresUnreferencedCode ("AOT")]
+    [RequiresDynamicCode ("AOT")]
+    public static void Init (ConsoleDriver driver = null, string driverName = null) { InternalInit (driver, driverName); }
+
+    internal static bool _initialized;
+    internal static int _mainThreadId = -1;
+
+
+    // INTERNAL function for initializing an app with a Toplevel factory object, driver, and mainloop.
+    //
+    // Called from:
+    //
+    // Init() - When the user wants to use the default Toplevel. calledViaRunT will be false, causing all state to be reset.
+    // Run<T>() - When the user wants to use a custom Toplevel. calledViaRunT will be true, enabling Run<T>() to be called without calling Init first.
+    // Unit Tests - To initialize the app with a custom Toplevel, using the FakeDriver. calledViaRunT will be false, causing all state to be reset.
+    //
+    // calledViaRunT: If false (default) all state will be reset. If true the state will not be reset.
+    [RequiresUnreferencedCode ("AOT")]
+    [RequiresDynamicCode ("AOT")]
+    internal static void InternalInit (
+        ConsoleDriver driver = null,
+        string driverName = null,
+        bool calledViaRunT = false
+    )
+    {
+        if (_initialized && driver is null)
+        {
+            return;
+        }
+
+        if (_initialized)
+        {
+            throw new InvalidOperationException ("Init has already been called and must be bracketed by Shutdown.");
+        }
+
+        if (!calledViaRunT)
+        {
+            // Reset all class variables (Application is a singleton).
+            ResetState ();
+        }
+
+        // For UnitTests
+        if (driver is { })
+        {
+            Driver = driver;
+        }
+
+        // Start the process of configuration management.
+        // Note that we end up calling LoadConfigurationFromAllSources
+        // multiple times. We need to do this because some settings are only
+        // valid after a Driver is loaded. In this case we need just
+        // `Settings` so we can determine which driver to use.
+        // Don't reset, so we can inherit the theme from the previous run.
+        Load ();
+        Apply ();
+
+        // Ignore Configuration for ForceDriver if driverName is specified
+        if (!string.IsNullOrEmpty (driverName))
+        {
+            ForceDriver = driverName;
+        }
+
+        if (Driver is null)
+        {
+            PlatformID p = Environment.OSVersion.Platform;
+
+            if (string.IsNullOrEmpty (ForceDriver))
+            {
+                if (p == PlatformID.Win32NT || p == PlatformID.Win32S || p == PlatformID.Win32Windows)
+                {
+                    Driver = new WindowsDriver ();
+                }
+                else
+                {
+                    Driver = new CursesDriver ();
+                }
+            }
+            else
+            {
+                List<Type> drivers = GetDriverTypes ();
+                Type driverType = drivers.FirstOrDefault (t => t.Name.Equals (ForceDriver, StringComparison.InvariantCultureIgnoreCase));
+
+                if (driverType is { })
+                {
+                    Driver = (ConsoleDriver)Activator.CreateInstance (driverType);
+                }
+                else
+                {
+                    throw new ArgumentException (
+                                                 $"Invalid driver name: {ForceDriver}. Valid names are {string.Join (", ", drivers.Select (t => t.Name))}"
+                                                );
+                }
+            }
+        }
+
+        try
+        {
+            MainLoop = Driver.Init ();
+        }
+        catch (InvalidOperationException ex)
+        {
+            // This is a case where the driver is unable to initialize the console.
+            // This can happen if the console is already in use by another process or
+            // if running in unit tests.
+            // In this case, we want to throw a more specific exception.
+            throw new InvalidOperationException (
+                                                 "Unable to initialize the console. This can happen if the console is already in use by another process or in unit tests.",
+                                                 ex
+                                                );
+        }
+
+        Driver.SizeChanged += (s, args) => OnSizeChanging (args);
+        Driver.KeyDown += (s, args) => OnKeyDown (args);
+        Driver.KeyUp += (s, args) => OnKeyUp (args);
+        Driver.MouseEvent += (s, args) => OnMouseEvent (args);
+
+        SynchronizationContext.SetSynchronizationContext (new MainLoopSyncContext ());
+
+        SupportedCultures = GetSupportedCultures ();
+        _mainThreadId = Thread.CurrentThread.ManagedThreadId;
+        _initialized = true;
+        InitializedChanged?.Invoke (null, new (in _initialized));
+    }
+
+    private static void Driver_SizeChanged (object sender, SizeChangedEventArgs e) { OnSizeChanging (e); }
+    private static void Driver_KeyDown (object sender, Key e) { OnKeyDown (e); }
+    private static void Driver_KeyUp (object sender, Key e) { OnKeyUp (e); }
+    private static void Driver_MouseEvent (object sender, MouseEvent e) { OnMouseEvent (e); }
+
+    /// <summary>Gets of list of <see cref="ConsoleDriver"/> types that are available.</summary>
+    /// <returns></returns>
+    [RequiresUnreferencedCode ("AOT")]
+    public static List<Type> GetDriverTypes ()
+    {
+        // use reflection to get the list of drivers
+        List<Type> driverTypes = new ();
+
+        foreach (Assembly asm in AppDomain.CurrentDomain.GetAssemblies ())
+        {
+            foreach (Type type in asm.GetTypes ())
+            {
+                if (type.IsSubclassOf (typeof (ConsoleDriver)) && !type.IsAbstract)
+                {
+                    driverTypes.Add (type);
+                }
+            }
+        }
+
+        return driverTypes;
+    }
+
+    /// <summary>Shutdown an application initialized with <see cref="Init"/>.</summary>
+    /// <remarks>
+    ///     Shutdown must be called for every call to <see cref="Init"/> or
+    ///     <see cref="Application.Run(Toplevel, Func{Exception, bool})"/> to ensure all resources are cleaned
+    ///     up (Disposed)
+    ///     and terminal settings are restored.
+    /// </remarks>
+    public static void Shutdown ()
+    {
+        // TODO: Throw an exception if Init hasn't been called.
+        ResetState ();
+        PrintJsonErrors ();
+        InitializedChanged?.Invoke (null, new (in _initialized));
+    }
+
+    /// <summary>
+    ///     This event is raised after the <see cref="Init"/> and <see cref="Shutdown"/> methods have been called.
+    /// </summary>
+    /// <remarks>
+    ///     Intended to support unit tests that need to know when the application has been initialized.
+    /// </remarks>
+    public static event EventHandler<EventArgs<bool>> InitializedChanged;
+}
diff --git a/Terminal.Gui/Application/ApplicationKeyboard.cs b/Terminal.Gui/Application/Application.Keyboard.cs
similarity index 99%
rename from Terminal.Gui/Application/ApplicationKeyboard.cs
rename to Terminal.Gui/Application/Application.Keyboard.cs
index be737968f..e8d698286 100644
--- a/Terminal.Gui/Application/ApplicationKeyboard.cs
+++ b/Terminal.Gui/Application/Application.Keyboard.cs
@@ -2,7 +2,7 @@
 
 namespace Terminal.Gui;
 
-partial class Application
+public static partial class Application // Keyboard handling
 {
     private static Key _alternateForwardKey = Key.Empty; // Defined in config.json
 
diff --git a/Terminal.Gui/Application/ApplicationMouse.cs b/Terminal.Gui/Application/Application.Mouse.cs
similarity index 98%
rename from Terminal.Gui/Application/ApplicationMouse.cs
rename to Terminal.Gui/Application/Application.Mouse.cs
index 9f2a95339..4d3fb6129 100644
--- a/Terminal.Gui/Application/ApplicationMouse.cs
+++ b/Terminal.Gui/Application/Application.Mouse.cs
@@ -1,6 +1,6 @@
 namespace Terminal.Gui;
 
-partial class Application
+public static partial class Application // Mouse handling
 {
     #region Mouse handling
 
@@ -272,7 +272,7 @@ partial class Application
 
             if (view is Adornment adornmentView)
             {
-                view = adornmentView.Parent.SuperView;
+                view = adornmentView.Parent!.SuperView;
             }
             else
             {
diff --git a/Terminal.Gui/Application/Application.Run.cs b/Terminal.Gui/Application/Application.Run.cs
new file mode 100644
index 000000000..34189d9fc
--- /dev/null
+++ b/Terminal.Gui/Application/Application.Run.cs
@@ -0,0 +1,863 @@
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+
+namespace Terminal.Gui;
+
+public static partial class Application // Run (Begin, Run, End, Stop)
+{
+    private static Toplevel _cachedRunStateToplevel;
+
+    /// <summary>
+    ///     Notify that a new <see cref="RunState"/> was created (<see cref="Begin(Toplevel)"/> was called). The token is
+    ///     created in <see cref="Begin(Toplevel)"/> and this event will be fired before that function exits.
+    /// </summary>
+    /// <remarks>
+    ///     If <see cref="EndAfterFirstIteration"/> is <see langword="true"/> callers to <see cref="Begin(Toplevel)"/>
+    ///     must also subscribe to <see cref="NotifyStopRunState"/> and manually dispose of the <see cref="RunState"/> token
+    ///     when the application is done.
+    /// </remarks>
+    public static event EventHandler<RunStateEventArgs> NotifyNewRunState;
+
+    /// <summary>Notify that an existent <see cref="RunState"/> is stopping (<see cref="End(RunState)"/> was called).</summary>
+    /// <remarks>
+    ///     If <see cref="EndAfterFirstIteration"/> is <see langword="true"/> callers to <see cref="Begin(Toplevel)"/>
+    ///     must also subscribe to <see cref="NotifyStopRunState"/> and manually dispose of the <see cref="RunState"/> token
+    ///     when the application is done.
+    /// </remarks>
+    public static event EventHandler<ToplevelEventArgs> NotifyStopRunState;
+
+    /// <summary>Building block API: Prepares the provided <see cref="Toplevel"/> for execution.</summary>
+    /// <returns>
+    ///     The <see cref="RunState"/> handle that needs to be passed to the <see cref="End(RunState)"/> method upon
+    ///     completion.
+    /// </returns>
+    /// <param name="toplevel">The <see cref="Toplevel"/> to prepare execution for.</param>
+    /// <remarks>
+    ///     This method prepares the provided <see cref="Toplevel"/> for running with the focus, it adds this to the list
+    ///     of <see cref="Toplevel"/>s, lays out the Subviews, focuses the first element, and draws the <see cref="Toplevel"/>
+    ///     in the screen. This is usually followed by executing the <see cref="RunLoop"/> method, and then the
+    ///     <see cref="End(RunState)"/> method upon termination which will undo these changes.
+    /// </remarks>
+    public static RunState Begin (Toplevel toplevel)
+    {
+        ArgumentNullException.ThrowIfNull (toplevel);
+
+#if DEBUG_IDISPOSABLE
+        Debug.Assert (!toplevel.WasDisposed);
+
+        if (_cachedRunStateToplevel is { } && _cachedRunStateToplevel != toplevel)
+        {
+            Debug.Assert (_cachedRunStateToplevel.WasDisposed);
+        }
+#endif
+
+        if (toplevel.IsOverlappedContainer && OverlappedTop != toplevel && OverlappedTop is { })
+        {
+            throw new InvalidOperationException ("Only one Overlapped Container is allowed.");
+        }
+
+        // Ensure the mouse is ungrabbed.
+        MouseGrabView = null;
+
+        var rs = new RunState (toplevel);
+
+        // View implements ISupportInitializeNotification which is derived from ISupportInitialize
+        if (!toplevel.IsInitialized)
+        {
+            toplevel.BeginInit ();
+            toplevel.EndInit ();
+        }
+
+#if DEBUG_IDISPOSABLE
+        if (Top is { } && toplevel != Top && !_topLevels.Contains (Top))
+        {
+            // This assertion confirm if the Top was already disposed
+            Debug.Assert (Top.WasDisposed);
+            Debug.Assert (Top == _cachedRunStateToplevel);
+        }
+#endif
+
+        lock (_topLevels)
+        {
+            if (Top is { } && toplevel != Top && !_topLevels.Contains (Top))
+            {
+                // If Top was already disposed and isn't on the Toplevels Stack,
+                // clean it up here if is the same as _cachedRunStateToplevel
+                if (Top == _cachedRunStateToplevel)
+                {
+                    Top = null;
+                }
+                else
+                {
+                    // Probably this will never hit
+                    throw new ObjectDisposedException (Top.GetType ().FullName);
+                }
+            }
+            else if (OverlappedTop is { } && toplevel != Top && _topLevels.Contains (Top))
+            {
+                Top.OnLeave (toplevel);
+            }
+
+            // BUGBUG: We should not depend on `Id` internally.
+            // BUGBUG: It is super unclear what this code does anyway.
+            if (string.IsNullOrEmpty (toplevel.Id))
+            {
+                var count = 1;
+                var id = (_topLevels.Count + count).ToString ();
+
+                while (_topLevels.Count > 0 && _topLevels.FirstOrDefault (x => x.Id == id) is { })
+                {
+                    count++;
+                    id = (_topLevels.Count + count).ToString ();
+                }
+
+                toplevel.Id = (_topLevels.Count + count).ToString ();
+
+                _topLevels.Push (toplevel);
+            }
+            else
+            {
+                Toplevel dup = _topLevels.FirstOrDefault (x => x.Id == toplevel.Id);
+
+                if (dup is null)
+                {
+                    _topLevels.Push (toplevel);
+                }
+            }
+
+            if (_topLevels.FindDuplicates (new ToplevelEqualityComparer ()).Count > 0)
+            {
+                throw new ArgumentException ("There are duplicates Toplevel IDs");
+            }
+        }
+
+        if (Top is null || toplevel.IsOverlappedContainer)
+        {
+            Top = toplevel;
+        }
+
+        var refreshDriver = true;
+
+        if (OverlappedTop is null
+            || toplevel.IsOverlappedContainer
+            || (Current?.Modal == false && toplevel.Modal)
+            || (Current?.Modal == false && !toplevel.Modal)
+            || (Current?.Modal == true && toplevel.Modal))
+        {
+            if (toplevel.Visible)
+            {
+                Current?.OnDeactivate (toplevel);
+                Toplevel previousCurrent = Current;
+                Current = toplevel;
+                Current.OnActivate (previousCurrent);
+
+                SetCurrentOverlappedAsTop ();
+            }
+            else
+            {
+                refreshDriver = false;
+            }
+        }
+        else if ((OverlappedTop != null
+                  && toplevel != OverlappedTop
+                  && Current?.Modal == true
+                  && !_topLevels.Peek ().Modal)
+                 || (OverlappedTop is { } && toplevel != OverlappedTop && Current?.Running == false))
+        {
+            refreshDriver = false;
+            MoveCurrent (toplevel);
+        }
+        else
+        {
+            refreshDriver = false;
+            MoveCurrent (Current);
+        }
+
+        toplevel.SetRelativeLayout (Driver.Screen.Size);
+
+        toplevel.LayoutSubviews ();
+        toplevel.PositionToplevels ();
+        toplevel.FocusFirst ();
+        BringOverlappedTopToFront ();
+
+        if (refreshDriver)
+        {
+            OverlappedTop?.OnChildLoaded (toplevel);
+            toplevel.OnLoaded ();
+            toplevel.SetNeedsDisplay ();
+            toplevel.Draw ();
+            Driver.UpdateScreen ();
+
+            if (PositionCursor (toplevel))
+            {
+                Driver.UpdateCursor ();
+            }
+        }
+
+        NotifyNewRunState?.Invoke (toplevel, new (rs));
+
+        return rs;
+    }
+
+    /// <summary>
+    ///     Calls <see cref="View.PositionCursor"/> on the most focused view in the view starting with <paramref name="view"/>.
+    /// </summary>
+    /// <remarks>
+    ///     Does nothing if <paramref name="view"/> is <see langword="null"/> or if the most focused view is not visible or
+    ///     enabled.
+    ///     <para>
+    ///         If the most focused view is not visible within it's superview, the cursor will be hidden.
+    ///     </para>
+    /// </remarks>
+    /// <returns><see langword="true"/> if a view positioned the cursor and the position is visible.</returns>
+    internal static bool PositionCursor (View view)
+    {
+        // Find the most focused view and position the cursor there.
+        View mostFocused = view?.MostFocused;
+
+        if (mostFocused is null)
+        {
+            if (view is { HasFocus: true })
+            {
+                mostFocused = view;
+            }
+            else
+            {
+                return false;
+            }
+        }
+
+        // If the view is not visible or enabled, don't position the cursor
+        if (!mostFocused.Visible || !mostFocused.Enabled)
+        {
+            Driver.GetCursorVisibility (out CursorVisibility current);
+
+            if (current != CursorVisibility.Invisible)
+            {
+                Driver.SetCursorVisibility (CursorVisibility.Invisible);
+            }
+
+            return false;
+        }
+
+        // If the view is not visible within it's superview, don't position the cursor
+        Rectangle mostFocusedViewport = mostFocused.ViewportToScreen (mostFocused.Viewport with { Location = Point.Empty });
+        Rectangle superViewViewport = mostFocused.SuperView?.ViewportToScreen (mostFocused.SuperView.Viewport with { Location = Point.Empty }) ?? Driver.Screen;
+
+        if (!superViewViewport.IntersectsWith (mostFocusedViewport))
+        {
+            return false;
+        }
+
+        Point? cursor = mostFocused.PositionCursor ();
+
+        Driver.GetCursorVisibility (out CursorVisibility currentCursorVisibility);
+
+        if (cursor is { })
+        {
+            // Convert cursor to screen coords
+            cursor = mostFocused.ViewportToScreen (mostFocused.Viewport with { Location = cursor.Value }).Location;
+
+            // If the cursor is not in a visible location in the SuperView, hide it
+            if (!superViewViewport.Contains (cursor.Value))
+            {
+                if (currentCursorVisibility != CursorVisibility.Invisible)
+                {
+                    Driver.SetCursorVisibility (CursorVisibility.Invisible);
+                }
+
+                return false;
+            }
+
+            // Show it
+            if (currentCursorVisibility == CursorVisibility.Invisible)
+            {
+                Driver.SetCursorVisibility (mostFocused.CursorVisibility);
+            }
+
+            return true;
+        }
+
+        if (currentCursorVisibility != CursorVisibility.Invisible)
+        {
+            Driver.SetCursorVisibility (CursorVisibility.Invisible);
+        }
+
+        return false;
+    }
+
+    /// <summary>
+    ///     Runs the application by creating a <see cref="Toplevel"/> object and calling
+    ///     <see cref="Run(Toplevel, Func{Exception, bool})"/>.
+    /// </summary>
+    /// <remarks>
+    ///     <para>Calling <see cref="Init"/> first is not needed as this function will initialize the application.</para>
+    ///     <para>
+    ///         <see cref="Shutdown"/> must be called when the application is closing (typically after Run> has returned) to
+    ///         ensure resources are cleaned up and terminal settings restored.
+    ///     </para>
+    ///     <para>
+    ///         The caller is responsible for disposing the object returned by this method.
+    ///     </para>
+    /// </remarks>
+    /// <returns>The created <see cref="Toplevel"/> object. The caller is responsible for disposing this object.</returns>
+    [RequiresUnreferencedCode ("AOT")]
+    [RequiresDynamicCode ("AOT")]
+    public static Toplevel Run (Func<Exception, bool> errorHandler = null, ConsoleDriver driver = null) { return Run<Toplevel> (errorHandler, driver); }
+
+    /// <summary>
+    ///     Runs the application by creating a <see cref="Toplevel"/>-derived object of type <c>T</c> and calling
+    ///     <see cref="Run(Toplevel, Func{Exception, bool})"/>.
+    /// </summary>
+    /// <remarks>
+    ///     <para>Calling <see cref="Init"/> first is not needed as this function will initialize the application.</para>
+    ///     <para>
+    ///         <see cref="Shutdown"/> must be called when the application is closing (typically after Run> has returned) to
+    ///         ensure resources are cleaned up and terminal settings restored.
+    ///     </para>
+    ///     <para>
+    ///         The caller is responsible for disposing the object returned by this method.
+    ///     </para>
+    /// </remarks>
+    /// <param name="errorHandler"></param>
+    /// <param name="driver">
+    ///     The <see cref="ConsoleDriver"/> to use. If not specified the default driver for the platform will
+    ///     be used ( <see cref="WindowsDriver"/>, <see cref="CursesDriver"/>, or <see cref="NetDriver"/>). Must be
+    ///     <see langword="null"/> if <see cref="Init"/> has already been called.
+    /// </param>
+    /// <returns>The created T object. The caller is responsible for disposing this object.</returns>
+    [RequiresUnreferencedCode ("AOT")]
+    [RequiresDynamicCode ("AOT")]
+    public static T Run<T> (Func<Exception, bool> errorHandler = null, ConsoleDriver driver = null)
+        where T : Toplevel, new ()
+    {
+        if (!_initialized)
+        {
+            // Init() has NOT been called.
+            InternalInit (driver, null, true);
+        }
+
+        var top = new T ();
+
+        Run (top, errorHandler);
+
+        return top;
+    }
+
+    /// <summary>Runs the Application using the provided <see cref="Toplevel"/> view.</summary>
+    /// <remarks>
+    ///     <para>
+    ///         This method is used to start processing events for the main application, but it is also used to run other
+    ///         modal <see cref="View"/>s such as <see cref="Dialog"/> boxes.
+    ///     </para>
+    ///     <para>
+    ///         To make a <see cref="Run(Terminal.Gui.Toplevel,System.Func{System.Exception,bool})"/> stop execution, call
+    ///         <see cref="Application.RequestStop"/>.
+    ///     </para>
+    ///     <para>
+    ///         Calling <see cref="Run(Terminal.Gui.Toplevel,System.Func{System.Exception,bool})"/> is equivalent to calling
+    ///         <see cref="Begin(Toplevel)"/>, followed by <see cref="RunLoop(RunState)"/>, and then calling
+    ///         <see cref="End(RunState)"/>.
+    ///     </para>
+    ///     <para>
+    ///         Alternatively, to have a program control the main loop and process events manually, call
+    ///         <see cref="Begin(Toplevel)"/> to set things up manually and then repeatedly call
+    ///         <see cref="RunLoop(RunState)"/> with the wait parameter set to false. By doing this the
+    ///         <see cref="RunLoop(RunState)"/> method will only process any pending events, timers, idle handlers and then
+    ///         return control immediately.
+    ///     </para>
+    ///     <para>When using <see cref="Run{T}"/> or
+    ///         <see cref="Run(System.Func{System.Exception,bool},Terminal.Gui.ConsoleDriver)"/>
+    ///         <see cref="Init"/> will be called automatically.
+    ///     </para>
+    ///     <para>
+    ///         RELEASE builds only: When <paramref name="errorHandler"/> is <see langword="null"/> any exceptions will be
+    ///         rethrown. Otherwise, if <paramref name="errorHandler"/> will be called. If <paramref name="errorHandler"/>
+    ///         returns <see langword="true"/> the <see cref="RunLoop(RunState)"/> will resume; otherwise this method will
+    ///         exit.
+    ///     </para>
+    /// </remarks>
+    /// <param name="view">The <see cref="Toplevel"/> to run as a modal.</param>
+    /// <param name="errorHandler">
+    ///     RELEASE builds only: Handler for any unhandled exceptions (resumes when returns true,
+    ///     rethrows when null).
+    /// </param>
+    public static void Run (Toplevel view, Func<Exception, bool> errorHandler = null)
+    {
+        ArgumentNullException.ThrowIfNull (view);
+
+        if (_initialized)
+        {
+            if (Driver is null)
+            {
+                // Disposing before throwing
+                view.Dispose ();
+
+                // This code path should be impossible because Init(null, null) will select the platform default driver
+                throw new InvalidOperationException (
+                                                     "Init() completed without a driver being set (this should be impossible); Run<T>() cannot be called."
+                                                    );
+            }
+        }
+        else
+        {
+            // Init() has NOT been called.
+            throw new InvalidOperationException (
+                                                 "Init() has not been called. Only Run() or Run<T>() can be used without calling Init()."
+                                                );
+        }
+
+        var resume = true;
+
+        while (resume)
+        {
+#if !DEBUG
+            try
+            {
+#endif
+            resume = false;
+            RunState runState = Begin (view);
+
+            // If EndAfterFirstIteration is true then the user must dispose of the runToken
+            // by using NotifyStopRunState event.
+            RunLoop (runState);
+
+            if (runState.Toplevel is null)
+            {
+#if DEBUG_IDISPOSABLE
+                Debug.Assert (_topLevels.Count == 0);
+#endif
+                runState.Dispose ();
+
+                return;
+            }
+
+            if (!EndAfterFirstIteration)
+            {
+                End (runState);
+            }
+#if !DEBUG
+            }
+            catch (Exception error)
+            {
+                if (errorHandler is null)
+                {
+                    throw;
+                }
+
+                resume = errorHandler (error);
+            }
+#endif
+        }
+    }
+
+    /// <summary>Adds a timeout to the application.</summary>
+    /// <remarks>
+    ///     When time specified passes, the callback will be invoked. If the callback returns true, the timeout will be
+    ///     reset, repeating the invocation. If it returns false, the timeout will stop and be removed. The returned value is a
+    ///     token that can be used to stop the timeout by calling <see cref="RemoveTimeout(object)"/>.
+    /// </remarks>
+    public static object AddTimeout (TimeSpan time, Func<bool> callback) { return MainLoop?.AddTimeout (time, callback); }
+
+    /// <summary>Removes a previously scheduled timeout</summary>
+    /// <remarks>The token parameter is the value returned by <see cref="AddTimeout"/>.</remarks>
+    /// Returns
+    /// <c>true</c>
+    /// if the timeout is successfully removed; otherwise,
+    /// <c>false</c>
+    /// .
+    /// This method also returns
+    /// <c>false</c>
+    /// if the timeout is not found.
+    public static bool RemoveTimeout (object token) { return MainLoop?.RemoveTimeout (token) ?? false; }
+
+    /// <summary>Runs <paramref name="action"/> on the thread that is processing events</summary>
+    /// <param name="action">the action to be invoked on the main processing thread.</param>
+    public static void Invoke (Action action)
+    {
+        MainLoop?.AddIdle (
+                           () =>
+                           {
+                               action ();
+
+                               return false;
+                           }
+                          );
+    }
+
+    /// <summary>Wakes up the running application that might be waiting on input.</summary>
+    public static void Wakeup () { MainLoop?.Wakeup (); }
+
+    /// <summary>Triggers a refresh of the entire display.</summary>
+    public static void Refresh ()
+    {
+        // TODO: Figure out how to remove this call to ClearContents. Refresh should just repaint damaged areas, not clear
+        Driver.ClearContents ();
+        View last = null;
+
+        foreach (Toplevel v in _topLevels.Reverse ())
+        {
+            if (v.Visible)
+            {
+                v.SetNeedsDisplay ();
+                v.SetSubViewNeedsDisplay ();
+                v.Draw ();
+            }
+
+            last = v;
+        }
+
+        Driver.Refresh ();
+    }
+
+    /// <summary>This event is raised on each iteration of the main loop.</summary>
+    /// <remarks>See also <see cref="Timeout"/></remarks>
+    public static event EventHandler<IterationEventArgs> Iteration;
+
+    /// <summary>The <see cref="MainLoop"/> driver for the application</summary>
+    /// <value>The main loop.</value>
+    internal static MainLoop MainLoop { get; private set; }
+
+    /// <summary>
+    ///     Set to true to cause <see cref="End"/> to be called after the first iteration. Set to false (the default) to
+    ///     cause the application to continue running until Application.RequestStop () is called.
+    /// </summary>
+    public static bool EndAfterFirstIteration { get; set; }
+
+    /// <summary>Building block API: Runs the main loop for the created <see cref="Toplevel"/>.</summary>
+    /// <param name="state">The state returned by the <see cref="Begin(Toplevel)"/> method.</param>
+    public static void RunLoop (RunState state)
+    {
+        ArgumentNullException.ThrowIfNull (state);
+        ObjectDisposedException.ThrowIf (state.Toplevel is null, "state");
+
+        var firstIteration = true;
+
+        for (state.Toplevel.Running = true; state.Toplevel?.Running == true;)
+        {
+            MainLoop.Running = true;
+
+            if (EndAfterFirstIteration && !firstIteration)
+            {
+                return;
+            }
+
+            RunIteration (ref state, ref firstIteration);
+        }
+
+        MainLoop.Running = false;
+
+        // Run one last iteration to consume any outstanding input events from Driver
+        // This is important for remaining OnKeyUp events.
+        RunIteration (ref state, ref firstIteration);
+    }
+
+    /// <summary>Run one application iteration.</summary>
+    /// <param name="state">The state returned by <see cref="Begin(Toplevel)"/>.</param>
+    /// <param name="firstIteration">
+    ///     Set to <see langword="true"/> if this is the first run loop iteration. Upon return, it
+    ///     will be set to <see langword="false"/> if at least one iteration happened.
+    /// </param>
+    public static void RunIteration (ref RunState state, ref bool firstIteration)
+    {
+        if (MainLoop.Running && MainLoop.EventsPending ())
+        {
+            // Notify Toplevel it's ready
+            if (firstIteration)
+            {
+                state.Toplevel.OnReady ();
+            }
+
+            MainLoop.RunIteration ();
+            Iteration?.Invoke (null, new ());
+            EnsureModalOrVisibleAlwaysOnTop (state.Toplevel);
+
+            if (state.Toplevel != Current)
+            {
+                OverlappedTop?.OnDeactivate (state.Toplevel);
+                state.Toplevel = Current;
+                OverlappedTop?.OnActivate (state.Toplevel);
+                Top.SetSubViewNeedsDisplay ();
+                Refresh ();
+            }
+        }
+
+        firstIteration = false;
+
+        if (Current == null)
+        {
+            return;
+        }
+
+        if (state.Toplevel != Top && (Top.NeedsDisplay || Top.SubViewNeedsDisplay || Top.LayoutNeeded))
+        {
+            state.Toplevel.SetNeedsDisplay (state.Toplevel.Frame);
+            Top.Draw ();
+
+            foreach (Toplevel top in _topLevels.Reverse ())
+            {
+                if (top != Top && top != state.Toplevel)
+                {
+                    top.SetNeedsDisplay ();
+                    top.SetSubViewNeedsDisplay ();
+                    top.Draw ();
+                }
+            }
+        }
+
+        if (_topLevels.Count == 1
+            && state.Toplevel == Top
+            && (Driver.Cols != state.Toplevel.Frame.Width
+                || Driver.Rows != state.Toplevel.Frame.Height)
+            && (state.Toplevel.NeedsDisplay
+                || state.Toplevel.SubViewNeedsDisplay
+                || state.Toplevel.LayoutNeeded))
+        {
+            Driver.ClearContents ();
+        }
+
+        if (state.Toplevel.NeedsDisplay || state.Toplevel.SubViewNeedsDisplay || state.Toplevel.LayoutNeeded || OverlappedChildNeedsDisplay ())
+        {
+            state.Toplevel.SetNeedsDisplay ();
+            state.Toplevel.Draw ();
+            Driver.UpdateScreen ();
+
+            //Driver.UpdateCursor ();
+        }
+
+        if (PositionCursor (state.Toplevel))
+        {
+            Driver.UpdateCursor ();
+        }
+
+        //        else
+        {
+            //if (PositionCursor (state.Toplevel))
+            //{
+            //    Driver.Refresh ();
+            //}
+            //Driver.UpdateCursor ();
+        }
+
+        if (state.Toplevel != Top && !state.Toplevel.Modal && (Top.NeedsDisplay || Top.SubViewNeedsDisplay || Top.LayoutNeeded))
+        {
+            Top.Draw ();
+        }
+    }
+
+    /// <summary>Stops the provided <see cref="Toplevel"/>, causing or the <paramref name="top"/> if provided.</summary>
+    /// <param name="top">The <see cref="Toplevel"/> to stop.</param>
+    /// <remarks>
+    ///     <para>This will cause <see cref="Application.Run(Toplevel, Func{Exception, bool})"/> to return.</para>
+    ///     <para>
+    ///         Calling <see cref="RequestStop(Terminal.Gui.Toplevel)"/> is equivalent to setting the <see cref="Toplevel.Running"/>
+    ///         property on the currently running <see cref="Toplevel"/> to false.
+    ///     </para>
+    /// </remarks>
+    public static void RequestStop (Toplevel top = null)
+    {
+        if (OverlappedTop is null || top is null || (OverlappedTop is null && top is { }))
+        {
+            top = Current;
+        }
+
+        if (OverlappedTop != null
+            && top.IsOverlappedContainer
+            && top?.Running == true
+            && (Current?.Modal == false || (Current?.Modal == true && Current?.Running == false)))
+        {
+            OverlappedTop.RequestStop ();
+        }
+        else if (OverlappedTop != null
+                 && top != Current
+                 && Current?.Running == true
+                 && Current?.Modal == true
+                 && top.Modal
+                 && top.Running)
+        {
+            var ev = new ToplevelClosingEventArgs (Current);
+            Current.OnClosing (ev);
+
+            if (ev.Cancel)
+            {
+                return;
+            }
+
+            ev = new (top);
+            top.OnClosing (ev);
+
+            if (ev.Cancel)
+            {
+                return;
+            }
+
+            Current.Running = false;
+            OnNotifyStopRunState (Current);
+            top.Running = false;
+            OnNotifyStopRunState (top);
+        }
+        else if ((OverlappedTop != null
+                  && top != OverlappedTop
+                  && top != Current
+                  && Current?.Modal == false
+                  && Current?.Running == true
+                  && !top.Running)
+                 || (OverlappedTop != null
+                     && top != OverlappedTop
+                     && top != Current
+                     && Current?.Modal == false
+                     && Current?.Running == false
+                     && !top.Running
+                     && _topLevels.ToArray () [1].Running))
+        {
+            MoveCurrent (top);
+        }
+        else if (OverlappedTop != null
+                 && Current != top
+                 && Current?.Running == true
+                 && !top.Running
+                 && Current?.Modal == true
+                 && top.Modal)
+        {
+            // The Current and the top are both modal so needed to set the Current.Running to false too.
+            Current.Running = false;
+            OnNotifyStopRunState (Current);
+        }
+        else if (OverlappedTop != null
+                 && Current == top
+                 && OverlappedTop?.Running == true
+                 && Current?.Running == true
+                 && top.Running
+                 && Current?.Modal == true
+                 && top.Modal)
+        {
+            // The OverlappedTop was requested to stop inside a modal Toplevel which is the Current and top,
+            // both are the same, so needed to set the Current.Running to false too.
+            Current.Running = false;
+            OnNotifyStopRunState (Current);
+        }
+        else
+        {
+            Toplevel currentTop;
+
+            if (top == Current || (Current?.Modal == true && !top.Modal))
+            {
+                currentTop = Current;
+            }
+            else
+            {
+                currentTop = top;
+            }
+
+            if (!currentTop.Running)
+            {
+                return;
+            }
+
+            var ev = new ToplevelClosingEventArgs (currentTop);
+            currentTop.OnClosing (ev);
+
+            if (ev.Cancel)
+            {
+                return;
+            }
+
+            currentTop.Running = false;
+            OnNotifyStopRunState (currentTop);
+        }
+    }
+
+    private static void OnNotifyStopRunState (Toplevel top)
+    {
+        if (EndAfterFirstIteration)
+        {
+            NotifyStopRunState?.Invoke (top, new (top));
+        }
+    }
+
+    /// <summary>
+    ///     Building block API: completes the execution of a <see cref="Toplevel"/> that was started with
+    ///     <see cref="Begin(Toplevel)"/> .
+    /// </summary>
+    /// <param name="runState">The <see cref="RunState"/> returned by the <see cref="Begin(Toplevel)"/> method.</param>
+    public static void End (RunState runState)
+    {
+        ArgumentNullException.ThrowIfNull (runState);
+
+        if (OverlappedTop is { })
+        {
+            OverlappedTop.OnChildUnloaded (runState.Toplevel);
+        }
+        else
+        {
+            runState.Toplevel.OnUnloaded ();
+        }
+
+        // End the RunState.Toplevel
+        // First, take it off the Toplevel Stack
+        if (_topLevels.Count > 0)
+        {
+            if (_topLevels.Peek () != runState.Toplevel)
+            {
+                // If the top of the stack is not the RunState.Toplevel then
+                // this call to End is not balanced with the call to Begin that started the RunState
+                throw new ArgumentException ("End must be balanced with calls to Begin");
+            }
+
+            _topLevels.Pop ();
+        }
+
+        // Notify that it is closing
+        runState.Toplevel?.OnClosed (runState.Toplevel);
+
+        // If there is a OverlappedTop that is not the RunState.Toplevel then RunState.Toplevel
+        // is a child of MidTop, and we should notify the OverlappedTop that it is closing
+        if (OverlappedTop is { } && !runState.Toplevel.Modal && runState.Toplevel != OverlappedTop)
+        {
+            OverlappedTop.OnChildClosed (runState.Toplevel);
+        }
+
+        // Set Current and Top to the next TopLevel on the stack
+        if (_topLevels.Count == 0)
+        {
+            Current = null;
+        }
+        else
+        {
+            if (_topLevels.Count > 1 && _topLevels.Peek () == OverlappedTop && OverlappedChildren.Any (t => t.Visible) is { })
+            {
+                OverlappedMoveNext ();
+            }
+
+            Current = _topLevels.Peek ();
+
+            if (_topLevels.Count == 1 && Current == OverlappedTop)
+            {
+                OverlappedTop.OnAllChildClosed ();
+            }
+            else
+            {
+                SetCurrentOverlappedAsTop ();
+                runState.Toplevel.OnLeave (Current);
+                Current.OnEnter (runState.Toplevel);
+            }
+
+            Refresh ();
+        }
+
+        // Don't dispose runState.Toplevel. It's up to caller dispose it
+        // If it's not the same as the current in the RunIteration,
+        // it will be fixed later in the next RunIteration.
+        if (OverlappedTop is { } && !_topLevels.Contains (OverlappedTop))
+        {
+            _cachedRunStateToplevel = OverlappedTop;
+        }
+        else
+        {
+            _cachedRunStateToplevel = runState.Toplevel;
+        }
+
+        runState.Toplevel = null;
+        runState.Dispose ();
+    }
+}
diff --git a/Terminal.Gui/Application/Application.cs b/Terminal.Gui/Application/Application.cs
index 9c981b743..1561413e9 100644
--- a/Terminal.Gui/Application/Application.cs
+++ b/Terminal.Gui/Application/Application.cs
@@ -1,5 +1,5 @@
+#nullable enable
 using System.Diagnostics;
-using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.Reflection;
 
@@ -18,31 +18,6 @@ namespace Terminal.Gui;
 /// <remarks>TODO: Flush this out.</remarks>
 public static partial class Application
 {
-    // For Unit testing - ignores UseSystemConsole
-    internal static bool _forceFakeConsole;
-
-    /// <summary>Gets the <see cref="ConsoleDriver"/> that has been selected. See also <see cref="ForceDriver"/>.</summary>
-    public static ConsoleDriver Driver { get; internal set; }
-
-    /// <summary>
-    ///     Gets or sets whether <see cref="Application.Driver"/> will be forced to output only the 16 colors defined in
-    ///     <see cref="ColorName"/>. The default is <see langword="false"/>, meaning 24-bit (TrueColor) colors will be output
-    ///     as long as the selected <see cref="ConsoleDriver"/> supports TrueColor.
-    /// </summary>
-    [SerializableConfigurationProperty (Scope = typeof (SettingsScope))]
-    public static bool Force16Colors { get; set; }
-
-    /// <summary>
-    ///     Forces the use of the specified driver (one of "fake", "ansi", "curses", "net", or "windows"). If not
-    ///     specified, the driver is selected based on the platform.
-    /// </summary>
-    /// <remarks>
-    ///     Note, <see cref="Application.Init(ConsoleDriver, string)"/> will override this configuration setting if called
-    ///     with either `driver` or `driverName` specified.
-    /// </remarks>
-    [SerializableConfigurationProperty (Scope = typeof (SettingsScope))]
-    public static string ForceDriver { get; set; } = string.Empty;
-
     /// <summary>Gets all cultures supported by the application without the invariant language.</summary>
     public static List<CultureInfo> SupportedCultures { get; private set; }
 
@@ -68,10 +43,6 @@ public static partial class Application
                       .ToList ();
     }
 
-    // When `End ()` is called, it is possible `RunState.Toplevel` is a different object than `Top`.
-    // This variable is set in `End` in this case so that `Begin` correctly sets `Top`.
-    private static Toplevel _cachedRunStateToplevel;
-
     // IMPORTANT: Ensure all property/fields are reset here. See Init_ResetState_Resets_Properties unit test.
     // Encapsulate all setting of initial state for Application; Having
     // this in a function like this ensures we don't make mistakes in
@@ -82,9 +53,9 @@ public static partial class Application
         // Shutdown is the bookend for Init. As such it needs to clean up all resources
         // Init created. Apps that do any threading will need to code defensively for this.
         // e.g. see Issue #537
-        foreach (Toplevel t in _topLevels)
+        foreach (Toplevel? t in _topLevels)
         {
-            t.Running = false;
+            t!.Running = false;
         }
 
         _topLevels.Clear ();
@@ -163,1072 +134,11 @@ public static partial class Application
         SynchronizationContext.SetSynchronizationContext (null);
     }
 
-    #region Initialization (Init/Shutdown)
-
-    /// <summary>Initializes a new instance of <see cref="Terminal.Gui"/> Application.</summary>
-    /// <para>Call this method once per instance (or after <see cref="Shutdown"/> has been called).</para>
-    /// <para>
-    ///     This function loads the right <see cref="ConsoleDriver"/> for the platform, Creates a <see cref="Toplevel"/>. and
-    ///     assigns it to <see cref="Top"/>
-    /// </para>
-    /// <para>
-    ///     <see cref="Shutdown"/> must be called when the application is closing (typically after
-    ///     <see cref="Run{T}"/> has returned) to ensure resources are cleaned up and
-    ///     terminal settings
-    ///     restored.
-    /// </para>
-    /// <para>
-    ///     The <see cref="Run{T}"/> function combines
-    ///     <see cref="Init(ConsoleDriver, string)"/> and <see cref="Run(Toplevel, Func{Exception, bool})"/>
-    ///     into a single
-    ///     call. An application cam use <see cref="Run{T}"/> without explicitly calling
-    ///     <see cref="Init(ConsoleDriver, string)"/>.
-    /// </para>
-    /// <param name="driver">
-    ///     The <see cref="ConsoleDriver"/> to use. If neither <paramref name="driver"/> or
-    ///     <paramref name="driverName"/> are specified the default driver for the platform will be used.
-    /// </param>
-    /// <param name="driverName">
-    ///     The short name (e.g. "net", "windows", "ansi", "fake", or "curses") of the
-    ///     <see cref="ConsoleDriver"/> to use. If neither <paramref name="driver"/> or <paramref name="driverName"/> are
-    ///     specified the default driver for the platform will be used.
-    /// </param>
-    [RequiresUnreferencedCode ("AOT")]
-    [RequiresDynamicCode ("AOT")]
-    public static void Init (ConsoleDriver driver = null, string driverName = null) { InternalInit (driver, driverName); }
-
-    internal static bool _initialized;
-    internal static int _mainThreadId = -1;
-
-    // INTERNAL function for initializing an app with a Toplevel factory object, driver, and mainloop.
-    //
-    // Called from:
-    //
-    // Init() - When the user wants to use the default Toplevel. calledViaRunT will be false, causing all state to be reset.
-    // Run<T>() - When the user wants to use a custom Toplevel. calledViaRunT will be true, enabling Run<T>() to be called without calling Init first.
-    // Unit Tests - To initialize the app with a custom Toplevel, using the FakeDriver. calledViaRunT will be false, causing all state to be reset.
-    //
-    // calledViaRunT: If false (default) all state will be reset. If true the state will not be reset.
-    [RequiresUnreferencedCode ("AOT")]
-    [RequiresDynamicCode ("AOT")]
-    internal static void InternalInit (
-        ConsoleDriver driver = null,
-        string driverName = null,
-        bool calledViaRunT = false
-    )
-    {
-        if (_initialized && driver is null)
-        {
-            return;
-        }
-
-        if (_initialized)
-        {
-            throw new InvalidOperationException ("Init has already been called and must be bracketed by Shutdown.");
-        }
-
-        if (!calledViaRunT)
-        {
-            // Reset all class variables (Application is a singleton).
-            ResetState ();
-        }
-
-        // For UnitTests
-        if (driver is { })
-        {
-            Driver = driver;
-        }
-
-        // Start the process of configuration management.
-        // Note that we end up calling LoadConfigurationFromAllSources
-        // multiple times. We need to do this because some settings are only
-        // valid after a Driver is loaded. In this case we need just
-        // `Settings` so we can determine which driver to use.
-        // Don't reset, so we can inherit the theme from the previous run.
-        Load ();
-        Apply ();
-
-        // Ignore Configuration for ForceDriver if driverName is specified
-        if (!string.IsNullOrEmpty (driverName))
-        {
-            ForceDriver = driverName;
-        }
-
-        if (Driver is null)
-        {
-            PlatformID p = Environment.OSVersion.Platform;
-
-            if (string.IsNullOrEmpty (ForceDriver))
-            {
-                if (p == PlatformID.Win32NT || p == PlatformID.Win32S || p == PlatformID.Win32Windows)
-                {
-                    Driver = new WindowsDriver ();
-                }
-                else
-                {
-                    Driver = new CursesDriver ();
-                }
-            }
-            else
-            {
-                List<Type> drivers = GetDriverTypes ();
-                Type driverType = drivers.FirstOrDefault (t => t.Name.Equals (ForceDriver, StringComparison.InvariantCultureIgnoreCase));
-
-                if (driverType is { })
-                {
-                    Driver = (ConsoleDriver)Activator.CreateInstance (driverType);
-                }
-                else
-                {
-                    throw new ArgumentException (
-                                                 $"Invalid driver name: {ForceDriver}. Valid names are {string.Join (", ", drivers.Select (t => t.Name))}"
-                                                );
-                }
-            }
-        }
-
-        try
-        {
-            MainLoop = Driver.Init ();
-        }
-        catch (InvalidOperationException ex)
-        {
-            // This is a case where the driver is unable to initialize the console.
-            // This can happen if the console is already in use by another process or
-            // if running in unit tests.
-            // In this case, we want to throw a more specific exception.
-            throw new InvalidOperationException (
-                                                 "Unable to initialize the console. This can happen if the console is already in use by another process or in unit tests.",
-                                                 ex
-                                                );
-        }
-
-        Driver.SizeChanged += (s, args) => OnSizeChanging (args);
-        Driver.KeyDown += (s, args) => OnKeyDown (args);
-        Driver.KeyUp += (s, args) => OnKeyUp (args);
-        Driver.MouseEvent += (s, args) => OnMouseEvent (args);
-
-        SynchronizationContext.SetSynchronizationContext (new MainLoopSyncContext ());
-
-        SupportedCultures = GetSupportedCultures ();
-        _mainThreadId = Thread.CurrentThread.ManagedThreadId;
-        _initialized = true;
-        InitializedChanged?.Invoke (null, new (in _initialized));
-    }
-
-    private static void Driver_SizeChanged (object sender, SizeChangedEventArgs e) { OnSizeChanging (e); }
-    private static void Driver_KeyDown (object sender, Key e) { OnKeyDown (e); }
-    private static void Driver_KeyUp (object sender, Key e) { OnKeyUp (e); }
-    private static void Driver_MouseEvent (object sender, MouseEvent e) { OnMouseEvent (e); }
-
-    /// <summary>Gets of list of <see cref="ConsoleDriver"/> types that are available.</summary>
-    /// <returns></returns>
-    [RequiresUnreferencedCode ("AOT")]
-    public static List<Type> GetDriverTypes ()
-    {
-        // use reflection to get the list of drivers
-        List<Type> driverTypes = new ();
-
-        foreach (Assembly asm in AppDomain.CurrentDomain.GetAssemblies ())
-        {
-            foreach (Type type in asm.GetTypes ())
-            {
-                if (type.IsSubclassOf (typeof (ConsoleDriver)) && !type.IsAbstract)
-                {
-                    driverTypes.Add (type);
-                }
-            }
-        }
-
-        return driverTypes;
-    }
-
-    /// <summary>Shutdown an application initialized with <see cref="Init"/>.</summary>
-    /// <remarks>
-    ///     Shutdown must be called for every call to <see cref="Init"/> or
-    ///     <see cref="Application.Run(Toplevel, Func{Exception, bool})"/> to ensure all resources are cleaned
-    ///     up (Disposed)
-    ///     and terminal settings are restored.
-    /// </remarks>
-    public static void Shutdown ()
-    {
-        // TODO: Throw an exception if Init hasn't been called.
-        ResetState ();
-        PrintJsonErrors ();
-        InitializedChanged?.Invoke (null, new (in _initialized));
-    }
-
-#nullable enable
-    /// <summary>
-    ///     This event is raised after the <see cref="Init"/> and <see cref="Shutdown"/> methods have been called.
-    /// </summary>
-    /// <remarks>
-    ///     Intended to support unit tests that need to know when the application has been initialized.
-    /// </remarks>
-    public static event EventHandler<EventArgs<bool>>? InitializedChanged;
-#nullable restore
-
-    #endregion Initialization (Init/Shutdown)
-
-    #region Run (Begin, Run, End, Stop)
-
-    /// <summary>
-    ///     Notify that a new <see cref="RunState"/> was created (<see cref="Begin(Toplevel)"/> was called). The token is
-    ///     created in <see cref="Begin(Toplevel)"/> and this event will be fired before that function exits.
-    /// </summary>
-    /// <remarks>
-    ///     If <see cref="EndAfterFirstIteration"/> is <see langword="true"/> callers to <see cref="Begin(Toplevel)"/>
-    ///     must also subscribe to <see cref="NotifyStopRunState"/> and manually dispose of the <see cref="RunState"/> token
-    ///     when the application is done.
-    /// </remarks>
-    public static event EventHandler<RunStateEventArgs> NotifyNewRunState;
-
-    /// <summary>Notify that an existent <see cref="RunState"/> is stopping (<see cref="End(RunState)"/> was called).</summary>
-    /// <remarks>
-    ///     If <see cref="EndAfterFirstIteration"/> is <see langword="true"/> callers to <see cref="Begin(Toplevel)"/>
-    ///     must also subscribe to <see cref="NotifyStopRunState"/> and manually dispose of the <see cref="RunState"/> token
-    ///     when the application is done.
-    /// </remarks>
-    public static event EventHandler<ToplevelEventArgs> NotifyStopRunState;
-
-    /// <summary>Building block API: Prepares the provided <see cref="Toplevel"/> for execution.</summary>
-    /// <returns>
-    ///     The <see cref="RunState"/> handle that needs to be passed to the <see cref="End(RunState)"/> method upon
-    ///     completion.
-    /// </returns>
-    /// <param name="toplevel">The <see cref="Toplevel"/> to prepare execution for.</param>
-    /// <remarks>
-    ///     This method prepares the provided <see cref="Toplevel"/> for running with the focus, it adds this to the list
-    ///     of <see cref="Toplevel"/>s, lays out the Subviews, focuses the first element, and draws the <see cref="Toplevel"/>
-    ///     in the screen. This is usually followed by executing the <see cref="RunLoop"/> method, and then the
-    ///     <see cref="End(RunState)"/> method upon termination which will undo these changes.
-    /// </remarks>
-    public static RunState Begin (Toplevel toplevel)
-    {
-        ArgumentNullException.ThrowIfNull (toplevel);
-
-#if DEBUG_IDISPOSABLE
-        Debug.Assert (!toplevel.WasDisposed);
-
-        if (_cachedRunStateToplevel is { } && _cachedRunStateToplevel != toplevel)
-        {
-            Debug.Assert (_cachedRunStateToplevel.WasDisposed);
-        }
-#endif
-
-        if (toplevel.IsOverlappedContainer && OverlappedTop != toplevel && OverlappedTop is { })
-        {
-            throw new InvalidOperationException ("Only one Overlapped Container is allowed.");
-        }
-
-        // Ensure the mouse is ungrabbed.
-        MouseGrabView = null;
-
-        var rs = new RunState (toplevel);
-
-        // View implements ISupportInitializeNotification which is derived from ISupportInitialize
-        if (!toplevel.IsInitialized)
-        {
-            toplevel.BeginInit ();
-            toplevel.EndInit ();
-        }
-
-#if DEBUG_IDISPOSABLE
-        if (Top is { } && toplevel != Top && !_topLevels.Contains (Top))
-        {
-            // This assertion confirm if the Top was already disposed
-            Debug.Assert (Top.WasDisposed);
-            Debug.Assert (Top == _cachedRunStateToplevel);
-        }
-#endif
-
-        lock (_topLevels)
-        {
-            if (Top is { } && toplevel != Top && !_topLevels.Contains (Top))
-            {
-                // If Top was already disposed and isn't on the Toplevels Stack,
-                // clean it up here if is the same as _cachedRunStateToplevel
-                if (Top == _cachedRunStateToplevel)
-                {
-                    Top = null;
-                }
-                else
-                {
-                    // Probably this will never hit
-                    throw new ObjectDisposedException (Top.GetType ().FullName);
-                }
-            }
-            else if (OverlappedTop is { } && toplevel != Top && _topLevels.Contains (Top))
-            {
-                Top.OnLeave (toplevel);
-            }
-
-            // BUGBUG: We should not depend on `Id` internally.
-            // BUGBUG: It is super unclear what this code does anyway.
-            if (string.IsNullOrEmpty (toplevel.Id))
-            {
-                var count = 1;
-                var id = (_topLevels.Count + count).ToString ();
-
-                while (_topLevels.Count > 0 && _topLevels.FirstOrDefault (x => x.Id == id) is { })
-                {
-                    count++;
-                    id = (_topLevels.Count + count).ToString ();
-                }
-
-                toplevel.Id = (_topLevels.Count + count).ToString ();
-
-                _topLevels.Push (toplevel);
-            }
-            else
-            {
-                Toplevel dup = _topLevels.FirstOrDefault (x => x.Id == toplevel.Id);
-
-                if (dup is null)
-                {
-                    _topLevels.Push (toplevel);
-                }
-            }
-
-            if (_topLevels.FindDuplicates (new ToplevelEqualityComparer ()).Count > 0)
-            {
-                throw new ArgumentException ("There are duplicates Toplevel IDs");
-            }
-        }
-
-        if (Top is null || toplevel.IsOverlappedContainer)
-        {
-            Top = toplevel;
-        }
-
-        var refreshDriver = true;
-
-        if (OverlappedTop is null
-            || toplevel.IsOverlappedContainer
-            || (Current?.Modal == false && toplevel.Modal)
-            || (Current?.Modal == false && !toplevel.Modal)
-            || (Current?.Modal == true && toplevel.Modal))
-        {
-            if (toplevel.Visible)
-            {
-                Current?.OnDeactivate (toplevel);
-                Toplevel previousCurrent = Current;
-                Current = toplevel;
-                Current.OnActivate (previousCurrent);
-
-                SetCurrentOverlappedAsTop ();
-            }
-            else
-            {
-                refreshDriver = false;
-            }
-        }
-        else if ((OverlappedTop != null
-                  && toplevel != OverlappedTop
-                  && Current?.Modal == true
-                  && !_topLevels.Peek ().Modal)
-                 || (OverlappedTop is { } && toplevel != OverlappedTop && Current?.Running == false))
-        {
-            refreshDriver = false;
-            MoveCurrent (toplevel);
-        }
-        else
-        {
-            refreshDriver = false;
-            MoveCurrent (Current);
-        }
-
-        toplevel.SetRelativeLayout (Driver.Screen.Size);
-
-        toplevel.LayoutSubviews ();
-        toplevel.PositionToplevels ();
-        toplevel.FocusFirst ();
-        BringOverlappedTopToFront ();
-
-        if (refreshDriver)
-        {
-            OverlappedTop?.OnChildLoaded (toplevel);
-            toplevel.OnLoaded ();
-            toplevel.SetNeedsDisplay ();
-            toplevel.Draw ();
-            Driver.UpdateScreen ();
-
-            if (PositionCursor (toplevel))
-            {
-                Driver.UpdateCursor ();
-            }
-        }
-
-        NotifyNewRunState?.Invoke (toplevel, new (rs));
-
-        return rs;
-    }
-
-    /// <summary>
-    ///     Calls <see cref="View.PositionCursor"/> on the most focused view in the view starting with <paramref name="view"/>.
-    /// </summary>
-    /// <remarks>
-    ///     Does nothing if <paramref name="view"/> is <see langword="null"/> or if the most focused view is not visible or
-    ///     enabled.
-    ///     <para>
-    ///         If the most focused view is not visible within it's superview, the cursor will be hidden.
-    ///     </para>
-    /// </remarks>
-    /// <returns><see langword="true"/> if a view positioned the cursor and the position is visible.</returns>
-    internal static bool PositionCursor (View view)
-    {
-        // Find the most focused view and position the cursor there.
-        View mostFocused = view?.MostFocused;
-
-        if (mostFocused is null)
-        {
-            if (view is { HasFocus: true })
-            {
-                mostFocused = view;
-            }
-            else
-            {
-                return false;
-            }
-        }
-
-        // If the view is not visible or enabled, don't position the cursor
-        if (!mostFocused.Visible || !mostFocused.Enabled)
-        {
-            Driver.GetCursorVisibility (out CursorVisibility current);
-
-            if (current != CursorVisibility.Invisible)
-            {
-                Driver.SetCursorVisibility (CursorVisibility.Invisible);
-            }
-
-            return false;
-        }
-
-        // If the view is not visible within it's superview, don't position the cursor
-        Rectangle mostFocusedViewport = mostFocused.ViewportToScreen (mostFocused.Viewport with { Location = Point.Empty });
-        Rectangle superViewViewport = mostFocused.SuperView?.ViewportToScreen (mostFocused.SuperView.Viewport with { Location = Point.Empty }) ?? Driver.Screen;
-
-        if (!superViewViewport.IntersectsWith (mostFocusedViewport))
-        {
-            return false;
-        }
-
-        Point? cursor = mostFocused.PositionCursor ();
-
-        Driver.GetCursorVisibility (out CursorVisibility currentCursorVisibility);
-
-        if (cursor is { })
-        {
-            // Convert cursor to screen coords
-            cursor = mostFocused.ViewportToScreen (mostFocused.Viewport with { Location = cursor.Value }).Location;
-
-            // If the cursor is not in a visible location in the SuperView, hide it
-            if (!superViewViewport.Contains (cursor.Value))
-            {
-                if (currentCursorVisibility != CursorVisibility.Invisible)
-                {
-                    Driver.SetCursorVisibility (CursorVisibility.Invisible);
-                }
-
-                return false;
-            }
-
-            // Show it
-            if (currentCursorVisibility == CursorVisibility.Invisible)
-            {
-                Driver.SetCursorVisibility (mostFocused.CursorVisibility);
-            }
-
-            return true;
-        }
-
-        if (currentCursorVisibility != CursorVisibility.Invisible)
-        {
-            Driver.SetCursorVisibility (CursorVisibility.Invisible);
-        }
-
-        return false;
-    }
-
-    /// <summary>
-    ///     Runs the application by creating a <see cref="Toplevel"/> object and calling
-    ///     <see cref="Run(Toplevel, Func{Exception, bool})"/>.
-    /// </summary>
-    /// <remarks>
-    ///     <para>Calling <see cref="Init"/> first is not needed as this function will initialize the application.</para>
-    ///     <para>
-    ///         <see cref="Shutdown"/> must be called when the application is closing (typically after Run> has returned) to
-    ///         ensure resources are cleaned up and terminal settings restored.
-    ///     </para>
-    ///     <para>
-    ///         The caller is responsible for disposing the object returned by this method.
-    ///     </para>
-    /// </remarks>
-    /// <returns>The created <see cref="Toplevel"/> object. The caller is responsible for disposing this object.</returns>
-    [RequiresUnreferencedCode ("AOT")]
-    [RequiresDynamicCode ("AOT")]
-    public static Toplevel Run (Func<Exception, bool> errorHandler = null, ConsoleDriver driver = null) { return Run<Toplevel> (errorHandler, driver); }
-
-    /// <summary>
-    ///     Runs the application by creating a <see cref="Toplevel"/>-derived object of type <c>T</c> and calling
-    ///     <see cref="Run(Toplevel, Func{Exception, bool})"/>.
-    /// </summary>
-    /// <remarks>
-    ///     <para>Calling <see cref="Init"/> first is not needed as this function will initialize the application.</para>
-    ///     <para>
-    ///         <see cref="Shutdown"/> must be called when the application is closing (typically after Run> has returned) to
-    ///         ensure resources are cleaned up and terminal settings restored.
-    ///     </para>
-    ///     <para>
-    ///         The caller is responsible for disposing the object returned by this method.
-    ///     </para>
-    /// </remarks>
-    /// <param name="errorHandler"></param>
-    /// <param name="driver">
-    ///     The <see cref="ConsoleDriver"/> to use. If not specified the default driver for the platform will
-    ///     be used ( <see cref="WindowsDriver"/>, <see cref="CursesDriver"/>, or <see cref="NetDriver"/>). Must be
-    ///     <see langword="null"/> if <see cref="Init"/> has already been called.
-    /// </param>
-    /// <returns>The created T object. The caller is responsible for disposing this object.</returns>
-    [RequiresUnreferencedCode ("AOT")]
-    [RequiresDynamicCode ("AOT")]
-    public static T Run<T> (Func<Exception, bool> errorHandler = null, ConsoleDriver driver = null)
-        where T : Toplevel, new()
-    {
-        if (!_initialized)
-        {
-            // Init() has NOT been called.
-            InternalInit (driver, null, true);
-        }
-
-        var top = new T ();
-
-        Run (top, errorHandler);
-
-        return top;
-    }
-
-    /// <summary>Runs the Application using the provided <see cref="Toplevel"/> view.</summary>
-    /// <remarks>
-    ///     <para>
-    ///         This method is used to start processing events for the main application, but it is also used to run other
-    ///         modal <see cref="View"/>s such as <see cref="Dialog"/> boxes.
-    ///     </para>
-    ///     <para>
-    ///         To make a <see cref="Run(Toplevel, Func{Exception, bool})"/> stop execution, call
-    ///         <see cref="Application.RequestStop"/>.
-    ///     </para>
-    ///     <para>
-    ///         Calling <see cref="Run(Toplevel, Func{Exception, bool})"/> is equivalent to calling
-    ///         <see cref="Begin(Toplevel)"/>, followed by <see cref="RunLoop(RunState)"/>, and then calling
-    ///         <see cref="End(RunState)"/>.
-    ///     </para>
-    ///     <para>
-    ///         Alternatively, to have a program control the main loop and process events manually, call
-    ///         <see cref="Begin(Toplevel)"/> to set things up manually and then repeatedly call
-    ///         <see cref="RunLoop(RunState)"/> with the wait parameter set to false. By doing this the
-    ///         <see cref="RunLoop(RunState)"/> method will only process any pending events, timers, idle handlers and then
-    ///         return control immediately.
-    ///     </para>
-    ///     <para>When using <see cref="Run{T}"/> or
-    ///         <see cref="Run(System.Func{System.Exception,bool},Terminal.Gui.ConsoleDriver)"/>
-    ///         <see cref="Init"/> will be called automatically.
-    ///     </para>
-    ///     <para>
-    ///         RELEASE builds only: When <paramref name="errorHandler"/> is <see langword="null"/> any exceptions will be
-    ///         rethrown. Otherwise, if <paramref name="errorHandler"/> will be called. If <paramref name="errorHandler"/>
-    ///         returns <see langword="true"/> the <see cref="RunLoop(RunState)"/> will resume; otherwise this method will
-    ///         exit.
-    ///     </para>
-    /// </remarks>
-    /// <param name="view">The <see cref="Toplevel"/> to run as a modal.</param>
-    /// <param name="errorHandler">
-    ///     RELEASE builds only: Handler for any unhandled exceptions (resumes when returns true,
-    ///     rethrows when null).
-    /// </param>
-    public static void Run (Toplevel view, Func<Exception, bool> errorHandler = null)
-    {
-        ArgumentNullException.ThrowIfNull (view);
-
-        if (_initialized)
-        {
-            if (Driver is null)
-            {
-                // Disposing before throwing
-                view.Dispose ();
-
-                // This code path should be impossible because Init(null, null) will select the platform default driver
-                throw new InvalidOperationException (
-                                                     "Init() completed without a driver being set (this should be impossible); Run<T>() cannot be called."
-                                                    );
-            }
-        }
-        else
-        {
-            // Init() has NOT been called.
-            throw new InvalidOperationException (
-                                                 "Init() has not been called. Only Run() or Run<T>() can be used without calling Init()."
-                                                );
-        }
-
-        var resume = true;
-
-        while (resume)
-        {
-#if !DEBUG
-            try
-            {
-#endif
-            resume = false;
-            RunState runState = Begin (view);
-
-            // If EndAfterFirstIteration is true then the user must dispose of the runToken
-            // by using NotifyStopRunState event.
-            RunLoop (runState);
-
-            if (runState.Toplevel is null)
-            {
-#if DEBUG_IDISPOSABLE
-                Debug.Assert (_topLevels.Count == 0);
-#endif
-                runState.Dispose ();
-
-                return;
-            }
-
-            if (!EndAfterFirstIteration)
-            {
-                End (runState);
-            }
-#if !DEBUG
-            }
-            catch (Exception error)
-            {
-                if (errorHandler is null)
-                {
-                    throw;
-                }
-
-                resume = errorHandler (error);
-            }
-#endif
-        }
-    }
-
-    /// <summary>Adds a timeout to the application.</summary>
-    /// <remarks>
-    ///     When time specified passes, the callback will be invoked. If the callback returns true, the timeout will be
-    ///     reset, repeating the invocation. If it returns false, the timeout will stop and be removed. The returned value is a
-    ///     token that can be used to stop the timeout by calling <see cref="RemoveTimeout(object)"/>.
-    /// </remarks>
-    public static object AddTimeout (TimeSpan time, Func<bool> callback) { return MainLoop?.AddTimeout (time, callback); }
-
-    /// <summary>Removes a previously scheduled timeout</summary>
-    /// <remarks>The token parameter is the value returned by <see cref="AddTimeout"/>.</remarks>
-    /// Returns
-    /// <c>true</c>
-    /// if the timeout is successfully removed; otherwise,
-    /// <c>false</c>
-    /// .
-    /// This method also returns
-    /// <c>false</c>
-    /// if the timeout is not found.
-    public static bool RemoveTimeout (object token) { return MainLoop?.RemoveTimeout (token) ?? false; }
-
-    /// <summary>Runs <paramref name="action"/> on the thread that is processing events</summary>
-    /// <param name="action">the action to be invoked on the main processing thread.</param>
-    public static void Invoke (Action action)
-    {
-        MainLoop?.AddIdle (
-                           () =>
-                           {
-                               action ();
-
-                               return false;
-                           }
-                          );
-    }
+    // When `End ()` is called, it is possible `RunState.Toplevel` is a different object than `Top`.
+    // This field is set in `End` in this case so that `Begin` correctly sets `Top`.
 
     // TODO: Determine if this is really needed. The only code that calls WakeUp I can find
     // is ProgressBarStyles, and it's not clear it needs to.
-    /// <summary>Wakes up the running application that might be waiting on input.</summary>
-    public static void Wakeup () { MainLoop?.Wakeup (); }
-
-    /// <summary>Triggers a refresh of the entire display.</summary>
-    public static void Refresh ()
-    {
-        // TODO: Figure out how to remove this call to ClearContents. Refresh should just repaint damaged areas, not clear
-        Driver.ClearContents ();
-        View last = null;
-
-        foreach (Toplevel v in _topLevels.Reverse ())
-        {
-            if (v.Visible)
-            {
-                v.SetNeedsDisplay ();
-                v.SetSubViewNeedsDisplay ();
-                v.Draw ();
-            }
-
-            last = v;
-        }
-
-        Driver.Refresh ();
-    }
-
-    /// <summary>This event is raised on each iteration of the main loop.</summary>
-    /// <remarks>See also <see cref="Timeout"/></remarks>
-    public static event EventHandler<IterationEventArgs> Iteration;
-
-    /// <summary>The <see cref="MainLoop"/> driver for the application</summary>
-    /// <value>The main loop.</value>
-    internal static MainLoop MainLoop { get; private set; }
-
-    /// <summary>
-    ///     Set to true to cause <see cref="End"/> to be called after the first iteration. Set to false (the default) to
-    ///     cause the application to continue running until Application.RequestStop () is called.
-    /// </summary>
-    public static bool EndAfterFirstIteration { get; set; }
-
-    /// <summary>Building block API: Runs the main loop for the created <see cref="Toplevel"/>.</summary>
-    /// <param name="state">The state returned by the <see cref="Begin(Toplevel)"/> method.</param>
-    public static void RunLoop (RunState state)
-    {
-        ArgumentNullException.ThrowIfNull (state);
-        ObjectDisposedException.ThrowIf (state.Toplevel is null, "state");
-
-        var firstIteration = true;
-
-        for (state.Toplevel.Running = true; state.Toplevel?.Running == true;)
-        {
-            MainLoop.Running = true;
-
-            if (EndAfterFirstIteration && !firstIteration)
-            {
-                return;
-            }
-
-            RunIteration (ref state, ref firstIteration);
-        }
-
-        MainLoop.Running = false;
-
-        // Run one last iteration to consume any outstanding input events from Driver
-        // This is important for remaining OnKeyUp events.
-        RunIteration (ref state, ref firstIteration);
-    }
-
-    /// <summary>Run one application iteration.</summary>
-    /// <param name="state">The state returned by <see cref="Begin(Toplevel)"/>.</param>
-    /// <param name="firstIteration">
-    ///     Set to <see langword="true"/> if this is the first run loop iteration. Upon return, it
-    ///     will be set to <see langword="false"/> if at least one iteration happened.
-    /// </param>
-    public static void RunIteration (ref RunState state, ref bool firstIteration)
-    {
-        if (MainLoop.Running && MainLoop.EventsPending ())
-        {
-            // Notify Toplevel it's ready
-            if (firstIteration)
-            {
-                state.Toplevel.OnReady ();
-            }
-
-            MainLoop.RunIteration ();
-            Iteration?.Invoke (null, new ());
-            EnsureModalOrVisibleAlwaysOnTop (state.Toplevel);
-
-            if (state.Toplevel != Current)
-            {
-                OverlappedTop?.OnDeactivate (state.Toplevel);
-                state.Toplevel = Current;
-                OverlappedTop?.OnActivate (state.Toplevel);
-                Top.SetSubViewNeedsDisplay ();
-                Refresh ();
-            }
-        }
-
-        firstIteration = false;
-
-        if (Current == null)
-        {
-            return;
-        }
-
-        if (state.Toplevel != Top && (Top.NeedsDisplay || Top.SubViewNeedsDisplay || Top.LayoutNeeded))
-        {
-            state.Toplevel.SetNeedsDisplay (state.Toplevel.Frame);
-            Top.Draw ();
-
-            foreach (Toplevel top in _topLevels.Reverse ())
-            {
-                if (top != Top && top != state.Toplevel)
-                {
-                    top.SetNeedsDisplay ();
-                    top.SetSubViewNeedsDisplay ();
-                    top.Draw ();
-                }
-            }
-        }
-
-        if (_topLevels.Count == 1
-            && state.Toplevel == Top
-            && (Driver.Cols != state.Toplevel.Frame.Width
-                || Driver.Rows != state.Toplevel.Frame.Height)
-            && (state.Toplevel.NeedsDisplay
-                || state.Toplevel.SubViewNeedsDisplay
-                || state.Toplevel.LayoutNeeded))
-        {
-            Driver.ClearContents ();
-        }
-
-        if (state.Toplevel.NeedsDisplay || state.Toplevel.SubViewNeedsDisplay || state.Toplevel.LayoutNeeded || OverlappedChildNeedsDisplay ())
-        {
-            state.Toplevel.SetNeedsDisplay ();
-            state.Toplevel.Draw ();
-            Driver.UpdateScreen ();
-
-            //Driver.UpdateCursor ();
-        }
-
-        if (PositionCursor (state.Toplevel))
-        {
-            Driver.UpdateCursor ();
-        }
-
-        //        else
-        {
-            //if (PositionCursor (state.Toplevel))
-            //{
-            //    Driver.Refresh ();
-            //}
-            //Driver.UpdateCursor ();
-        }
-
-        if (state.Toplevel != Top && !state.Toplevel.Modal && (Top.NeedsDisplay || Top.SubViewNeedsDisplay || Top.LayoutNeeded))
-        {
-            Top.Draw ();
-        }
-    }
-
-    /// <summary>Stops the provided <see cref="Toplevel"/>, causing or the <paramref name="top"/> if provided.</summary>
-    /// <param name="top">The <see cref="Toplevel"/> to stop.</param>
-    /// <remarks>
-    ///     <para>This will cause <see cref="Application.Run(Toplevel, Func{Exception, bool})"/> to return.</para>
-    ///     <para>
-    ///         Calling <see cref="Application.RequestStop"/> is equivalent to setting the <see cref="Toplevel.Running"/>
-    ///         property on the currently running <see cref="Toplevel"/> to false.
-    ///     </para>
-    /// </remarks>
-    public static void RequestStop (Toplevel top = null)
-    {
-        if (OverlappedTop is null || top is null || (OverlappedTop is null && top is { }))
-        {
-            top = Current;
-        }
-
-        if (OverlappedTop != null
-            && top.IsOverlappedContainer
-            && top?.Running == true
-            && (Current?.Modal == false || (Current?.Modal == true && Current?.Running == false)))
-        {
-            OverlappedTop.RequestStop ();
-        }
-        else if (OverlappedTop != null
-                 && top != Current
-                 && Current?.Running == true
-                 && Current?.Modal == true
-                 && top.Modal
-                 && top.Running)
-        {
-            var ev = new ToplevelClosingEventArgs (Current);
-            Current.OnClosing (ev);
-
-            if (ev.Cancel)
-            {
-                return;
-            }
-
-            ev = new (top);
-            top.OnClosing (ev);
-
-            if (ev.Cancel)
-            {
-                return;
-            }
-
-            Current.Running = false;
-            OnNotifyStopRunState (Current);
-            top.Running = false;
-            OnNotifyStopRunState (top);
-        }
-        else if ((OverlappedTop != null
-                  && top != OverlappedTop
-                  && top != Current
-                  && Current?.Modal == false
-                  && Current?.Running == true
-                  && !top.Running)
-                 || (OverlappedTop != null
-                     && top != OverlappedTop
-                     && top != Current
-                     && Current?.Modal == false
-                     && Current?.Running == false
-                     && !top.Running
-                     && _topLevels.ToArray () [1].Running))
-        {
-            MoveCurrent (top);
-        }
-        else if (OverlappedTop != null
-                 && Current != top
-                 && Current?.Running == true
-                 && !top.Running
-                 && Current?.Modal == true
-                 && top.Modal)
-        {
-            // The Current and the top are both modal so needed to set the Current.Running to false too.
-            Current.Running = false;
-            OnNotifyStopRunState (Current);
-        }
-        else if (OverlappedTop != null
-                 && Current == top
-                 && OverlappedTop?.Running == true
-                 && Current?.Running == true
-                 && top.Running
-                 && Current?.Modal == true
-                 && top.Modal)
-        {
-            // The OverlappedTop was requested to stop inside a modal Toplevel which is the Current and top,
-            // both are the same, so needed to set the Current.Running to false too.
-            Current.Running = false;
-            OnNotifyStopRunState (Current);
-        }
-        else
-        {
-            Toplevel currentTop;
-
-            if (top == Current || (Current?.Modal == true && !top.Modal))
-            {
-                currentTop = Current;
-            }
-            else
-            {
-                currentTop = top;
-            }
-
-            if (!currentTop.Running)
-            {
-                return;
-            }
-
-            var ev = new ToplevelClosingEventArgs (currentTop);
-            currentTop.OnClosing (ev);
-
-            if (ev.Cancel)
-            {
-                return;
-            }
-
-            currentTop.Running = false;
-            OnNotifyStopRunState (currentTop);
-        }
-    }
-
-    private static void OnNotifyStopRunState (Toplevel top)
-    {
-        if (EndAfterFirstIteration)
-        {
-            NotifyStopRunState?.Invoke (top, new (top));
-        }
-    }
-
-    /// <summary>
-    ///     Building block API: completes the execution of a <see cref="Toplevel"/> that was started with
-    ///     <see cref="Begin(Toplevel)"/> .
-    /// </summary>
-    /// <param name="runState">The <see cref="RunState"/> returned by the <see cref="Begin(Toplevel)"/> method.</param>
-    public static void End (RunState runState)
-    {
-        ArgumentNullException.ThrowIfNull (runState);
-
-        if (OverlappedTop is { })
-        {
-            OverlappedTop.OnChildUnloaded (runState.Toplevel);
-        }
-        else
-        {
-            runState.Toplevel.OnUnloaded ();
-        }
-
-        // End the RunState.Toplevel
-        // First, take it off the Toplevel Stack
-        if (_topLevels.Count > 0)
-        {
-            if (_topLevels.Peek () != runState.Toplevel)
-            {
-                // If the top of the stack is not the RunState.Toplevel then
-                // this call to End is not balanced with the call to Begin that started the RunState
-                throw new ArgumentException ("End must be balanced with calls to Begin");
-            }
-
-            _topLevels.Pop ();
-        }
-
-        // Notify that it is closing
-        runState.Toplevel?.OnClosed (runState.Toplevel);
-
-        // If there is a OverlappedTop that is not the RunState.Toplevel then RunState.Toplevel
-        // is a child of MidTop, and we should notify the OverlappedTop that it is closing
-        if (OverlappedTop is { } && !runState.Toplevel.Modal && runState.Toplevel != OverlappedTop)
-        {
-            OverlappedTop.OnChildClosed (runState.Toplevel);
-        }
-
-        // Set Current and Top to the next TopLevel on the stack
-        if (_topLevels.Count == 0)
-        {
-            Current = null;
-        }
-        else
-        {
-            if (_topLevels.Count > 1 && _topLevels.Peek () == OverlappedTop && OverlappedChildren.Any (t => t.Visible) is { })
-            {
-                OverlappedMoveNext ();
-            }
-
-            Current = _topLevels.Peek ();
-
-            if (_topLevels.Count == 1 && Current == OverlappedTop)
-            {
-                OverlappedTop.OnAllChildClosed ();
-            }
-            else
-            {
-                SetCurrentOverlappedAsTop ();
-                runState.Toplevel.OnLeave (Current);
-                Current.OnEnter (runState.Toplevel);
-            }
-
-            Refresh ();
-        }
-
-        // Don't dispose runState.Toplevel. It's up to caller dispose it
-        // If it's not the same as the current in the RunIteration,
-        // it will be fixed later in the next RunIteration.
-        if (OverlappedTop is { } && !_topLevels.Contains (OverlappedTop))
-        {
-            _cachedRunStateToplevel = OverlappedTop;
-        }
-        else
-        {
-            _cachedRunStateToplevel = runState.Toplevel;
-        }
-
-        runState.Toplevel = null;
-        runState.Dispose ();
-    }
-
-    #endregion Run (Begin, Run, End)
 
     #region Toplevel handling
 
@@ -1240,7 +150,7 @@ public static partial class Application
 
     /// <summary>The <see cref="Toplevel"/> object used for the application on startup (<seealso cref="Application.Top"/>)</summary>
     /// <value>The top.</value>
-    public static Toplevel Top { get; private set; }
+    public static Toplevel? Top { get; private set; }
 
     /// <summary>
     ///     The current <see cref="Toplevel"/> object. This is updated in <see cref="Application.Begin"/> enters and leaves to
@@ -1251,7 +161,7 @@ public static partial class Application
     ///     Only relevant in scenarios where <see cref="Toplevel.IsOverlappedContainer"/> is <see langword="true"/>.
     /// </remarks>
     /// <value>The current.</value>
-    public static Toplevel Current { get; private set; }
+    public static Toplevel? Current { get; private set; }
 
     private static void EnsureModalOrVisibleAlwaysOnTop (Toplevel topLevel)
     {
@@ -1263,7 +173,7 @@ public static partial class Application
             return;
         }
 
-        foreach (Toplevel top in _topLevels.Reverse ())
+        foreach (Toplevel? top in _topLevels.Reverse ())
         {
             if (top.Modal && top != Current)
             {
@@ -1292,7 +202,7 @@ public static partial class Application
             int rx = location.X - start.Frame.X;
             int ry = location.Y - start.Frame.Y;
 
-            foreach (Toplevel t in _topLevels)
+            foreach (Toplevel? t in _topLevels)
             {
                 if (t != Current)
                 {
@@ -1327,7 +237,7 @@ public static partial class Application
 #nullable enable
 
     // Only return true if the Current has changed.
-    private static bool MoveCurrent (Toplevel? top)
+    private static bool MoveCurrent (Toplevel top)
     {
         // The Current is modal and the top is not modal Toplevel then
         // the Current must be moved above the first not modal Toplevel.
@@ -1343,9 +253,9 @@ public static partial class Application
             }
 
             var index = 0;
-            Toplevel [] savedToplevels = _topLevels.ToArray ();
+            Toplevel? [] savedToplevels = _topLevels.ToArray ();
 
-            foreach (Toplevel t in savedToplevels)
+            foreach (Toplevel? t in savedToplevels)
             {
                 if (!t.Modal && t != Current && t != top && t != savedToplevels [index])
                 {
@@ -1376,7 +286,7 @@ public static partial class Application
 
             var index = 0;
 
-            foreach (Toplevel t in _topLevels.ToArray ())
+            foreach (Toplevel? t in _topLevels.ToArray ())
             {
                 if (!t.Running && t != Current && index > 0)
                 {
@@ -1505,6 +415,7 @@ public static partial class Application
 
             sb.AppendLine ();
         }
+
         return sb.ToString ();
     }
 }
diff --git a/Terminal.Gui/Clipboard/Clipboard.cs b/Terminal.Gui/Clipboard/Clipboard.cs
index 63c1cc40a..5dccea0a4 100644
--- a/Terminal.Gui/Clipboard/Clipboard.cs
+++ b/Terminal.Gui/Clipboard/Clipboard.cs
@@ -31,11 +31,11 @@ public static class Clipboard
             {
                 if (IsSupported)
                 {
-                    string clipData = Application.Driver.Clipboard.GetClipboardData ();
+                    string clipData = Application.Driver?.Clipboard.GetClipboardData ();
 
                     if (clipData is null)
                     {
-                        // throw new InvalidOperationException ($"{Application.Driver.GetType ().Name}.GetClipboardData returned null instead of string.Empty");
+                        // throw new InvalidOperationException ($"{Application.Driver?.GetType ().Name}.GetClipboardData returned null instead of string.Empty");
                         clipData = string.Empty;
                     }
 
@@ -60,7 +60,7 @@ public static class Clipboard
                         value = string.Empty;
                     }
 
-                    Application.Driver.Clipboard.SetClipboardData (value);
+                    Application.Driver?.Clipboard.SetClipboardData (value);
                 }
 
                 _contents = value;
@@ -74,19 +74,16 @@ public static class Clipboard
 
     /// <summary>Returns true if the environmental dependencies are in place to interact with the OS clipboard.</summary>
     /// <remarks></remarks>
-    public static bool IsSupported => Application.Driver.Clipboard.IsSupported;
+    public static bool IsSupported => Application.Driver?.Clipboard.IsSupported ?? false;
 
     /// <summary>Copies the _contents of the OS clipboard to <paramref name="result"/> if possible.</summary>
     /// <param name="result">The _contents of the OS clipboard if successful, <see cref="string.Empty"/> if not.</param>
     /// <returns><see langword="true"/> the OS clipboard was retrieved, <see langword="false"/> otherwise.</returns>
     public static bool TryGetClipboardData (out string result)
     {
-        if (IsSupported && Application.Driver.Clipboard.TryGetClipboardData (out result))
+        if (IsSupported && Application.Driver!.Clipboard.TryGetClipboardData (out result))
         {
-            if (_contents != result)
-            {
-                _contents = result;
-            }
+            _contents = result;
 
             return true;
         }
@@ -101,7 +98,7 @@ public static class Clipboard
     /// <returns><see langword="true"/> the OS clipboard was set, <see langword="false"/> otherwise.</returns>
     public static bool TrySetClipboardData (string text)
     {
-        if (IsSupported && Application.Driver.Clipboard.TrySetClipboardData (text))
+        if (IsSupported && Application.Driver!.Clipboard.TrySetClipboardData (text))
         {
             _contents = text;
 
@@ -155,7 +152,7 @@ internal static class ClipboardProcessRunner
 
         using (var process = new Process
                {
-                   StartInfo = new ProcessStartInfo
+                   StartInfo = new()
                    {
                        FileName = cmd,
                        Arguments = arguments,
@@ -191,17 +188,9 @@ internal static class ClipboardProcessRunner
 
             if (process.ExitCode > 0)
             {
-                output = $@"Process failed to run. Command line: {
-                    cmd
-                } {
-                    arguments
-                }.
-										Output: {
-                                            output
-                                        }
-										Error: {
-                                            process.StandardError.ReadToEnd ()
-                                        }";
+                output = $@"Process failed to run. Command line: {cmd} {arguments}.
+										Output: {output}
+										Error: {process.StandardError.ReadToEnd ()}";
             }
 
             return (process.ExitCode, output);
diff --git a/Terminal.Gui/Drawing/LineCanvas.cs b/Terminal.Gui/Drawing/LineCanvas.cs
index 4b5119a82..9a7365f26 100644
--- a/Terminal.Gui/Drawing/LineCanvas.cs
+++ b/Terminal.Gui/Drawing/LineCanvas.cs
@@ -336,7 +336,7 @@ public class LineCanvas : IDisposable
         return Fill != null ? Fill.GetAttribute (intersects [0]!.Point) : intersects [0]!.Line.Attribute;
     }
 
-    private Cell? GetCellForIntersects (ConsoleDriver driver, IntersectionDefinition? [] intersects)
+    private Cell? GetCellForIntersects (ConsoleDriver? driver, IntersectionDefinition? [] intersects)
     {
         if (!intersects.Any ())
         {
@@ -356,7 +356,7 @@ public class LineCanvas : IDisposable
         return cell;
     }
 
-    private Rune? GetRuneForIntersects (ConsoleDriver driver, IntersectionDefinition? [] intersects)
+    private Rune? GetRuneForIntersects (ConsoleDriver? driver, IntersectionDefinition? [] intersects)
     {
         if (!intersects.Any ())
         {
@@ -679,7 +679,7 @@ public class LineCanvas : IDisposable
         internal Rune _thickV;
         public IntersectionRuneResolver () { SetGlyphs (); }
 
-        public Rune? GetRuneForIntersects (ConsoleDriver driver, IntersectionDefinition? [] intersects)
+        public Rune? GetRuneForIntersects (ConsoleDriver? driver, IntersectionDefinition? [] intersects)
         {
             bool useRounded = intersects.Any (
                                               i => i?.Line.Length != 0
diff --git a/Terminal.Gui/Drawing/Ruler.cs b/Terminal.Gui/Drawing/Ruler.cs
index 348036c84..d2551101d 100644
--- a/Terminal.Gui/Drawing/Ruler.cs
+++ b/Terminal.Gui/Drawing/Ruler.cs
@@ -39,8 +39,8 @@ public class Ruler
                 _hTemplate.Repeat ((int)Math.Ceiling (Length + 2 / (double)_hTemplate.Length)) [start..(Length + start)];
 
             // Top
-            Application.Driver.Move (location.X, location.Y);
-            Application.Driver.AddStr (hrule);
+            Application.Driver?.Move (location.X, location.Y);
+            Application.Driver?.AddStr (hrule);
         }
         else
         {
@@ -50,8 +50,8 @@ public class Ruler
 
             for (int r = location.Y; r < location.Y + Length; r++)
             {
-                Application.Driver.Move (location.X, r);
-                Application.Driver.AddRune ((Rune)vrule [r - location.Y]);
+                Application.Driver?.Move (location.X, r);
+                Application.Driver?.AddRune ((Rune)vrule [r - location.Y]);
             }
         }
     }
diff --git a/Terminal.Gui/Drawing/Thickness.cs b/Terminal.Gui/Drawing/Thickness.cs
index 532c0af8a..ac6cc6cd6 100644
--- a/Terminal.Gui/Drawing/Thickness.cs
+++ b/Terminal.Gui/Drawing/Thickness.cs
@@ -119,20 +119,20 @@ public record struct Thickness
         // Draw the Top side
         if (Top > 0)
         {
-            Application.Driver.FillRect (rect with { Height = Math.Min (rect.Height, Top) }, topChar);
+            Application.Driver?.FillRect (rect with { Height = Math.Min (rect.Height, Top) }, topChar);
         }
 
         // Draw the Left side
         // Draw the Left side
         if (Left > 0)
         {
-            Application.Driver.FillRect (rect with { Width = Math.Min (rect.Width, Left) }, leftChar);
+            Application.Driver?.FillRect (rect with { Width = Math.Min (rect.Width, Left) }, leftChar);
         }
 
         // Draw the Right side
         if (Right > 0)
         {
-            Application.Driver.FillRect (
+            Application.Driver?.FillRect (
                                          rect with
                                          {
                                              X = Math.Max (0, rect.X + rect.Width - Right),
@@ -145,7 +145,7 @@ public record struct Thickness
         // Draw the Bottom side
         if (Bottom > 0)
         {
-            Application.Driver.FillRect (
+            Application.Driver?.FillRect (
                                          rect with
                                          {
                                              Y = rect.Y + Math.Max (0, rect.Height - Bottom),
@@ -197,7 +197,11 @@ public record struct Thickness
                 VerticalAlignment = Alignment.End,
                 AutoSize = true
             };
-            tf.Draw (rect, Application.Driver.CurrentAttribute, Application.Driver.CurrentAttribute, rect);
+
+            if (Application.Driver?.CurrentAttribute is { })
+            {
+                tf.Draw (rect, Application.Driver!.CurrentAttribute, Application.Driver!.CurrentAttribute, rect);
+            }
         }
 
         return GetInside (rect);
diff --git a/Terminal.Gui/Text/Autocomplete/AppendAutocomplete.cs b/Terminal.Gui/Text/Autocomplete/AppendAutocomplete.cs
index f5f7190e6..2fa920e70 100644
--- a/Terminal.Gui/Text/Autocomplete/AppendAutocomplete.cs
+++ b/Terminal.Gui/Text/Autocomplete/AppendAutocomplete.cs
@@ -106,7 +106,7 @@ public class AppendAutocomplete : AutocompleteBase
         }
 
         // draw it like it's selected, even though it's not
-        Application.Driver.SetAttribute (
+        Application.Driver?.SetAttribute (
                                          new Attribute (
                                                         ColorScheme.Normal.Foreground,
                                                         textField.ColorScheme.Focus.Background
@@ -128,7 +128,7 @@ public class AppendAutocomplete : AutocompleteBase
                                   );
         }
 
-        Application.Driver.AddStr (fragment);
+        Application.Driver?.AddStr (fragment);
     }
 
     /// <summary>
diff --git a/Terminal.Gui/Text/Autocomplete/PopupAutocomplete.cs b/Terminal.Gui/Text/Autocomplete/PopupAutocomplete.cs
index 93e32b12e..4dfeb8a95 100644
--- a/Terminal.Gui/Text/Autocomplete/PopupAutocomplete.cs
+++ b/Terminal.Gui/Text/Autocomplete/PopupAutocomplete.cs
@@ -376,18 +376,18 @@ public abstract partial class PopupAutocomplete : AutocompleteBase
         {
             if (i == SelectedIdx - ScrollOffset)
             {
-                Application.Driver.SetAttribute (ColorScheme.Focus);
+                Application.Driver?.SetAttribute (ColorScheme.Focus);
             }
             else
             {
-                Application.Driver.SetAttribute (ColorScheme.Normal);
+                Application.Driver?.SetAttribute (ColorScheme.Normal);
             }
 
             popup.Move (0, i);
 
             string text = TextFormatter.ClipOrPad (toRender [i].Title, width);
 
-            Application.Driver.AddStr (text);
+            Application.Driver?.AddStr (text);
         }
     }
 
diff --git a/Terminal.Gui/View/Layout/Dim.cs b/Terminal.Gui/View/Layout/Dim.cs
index e765414cb..7dfc6eb2e 100644
--- a/Terminal.Gui/View/Layout/Dim.cs
+++ b/Terminal.Gui/View/Layout/Dim.cs
@@ -139,7 +139,7 @@ public abstract class Dim
     /// <summary>Creates a <see cref="Dim"/> object that tracks the Height of the specified <see cref="View"/>.</summary>
     /// <returns>The height <see cref="Dim"/> of the other <see cref="View"/>.</returns>
     /// <param name="view">The view that will be tracked.</param>
-    public static Dim Height (View view) { return new DimView (view, Dimension.Height); }
+    public static Dim Height (View? view) { return new DimView (view, Dimension.Height); }
 
     /// <summary>Creates a percentage <see cref="Dim"/> object that is a percentage of the width or height of the SuperView.</summary>
     /// <returns>The percent <see cref="Dim"/> object.</returns>
@@ -171,7 +171,7 @@ public abstract class Dim
     /// <summary>Creates a <see cref="Dim"/> object that tracks the Width of the specified <see cref="View"/>.</summary>
     /// <returns>The width <see cref="Dim"/> of the other <see cref="View"/>.</returns>
     /// <param name="view">The view that will be tracked.</param>
-    public static Dim Width (View view) { return new DimView (view, Dimension.Width); }
+    public static Dim Width (View? view) { return new DimView (view, Dimension.Width); }
 
     #endregion static Dim creation methods
 
diff --git a/Terminal.Gui/View/Layout/DimView.cs b/Terminal.Gui/View/Layout/DimView.cs
index 22c0d1f70..09ea96800 100644
--- a/Terminal.Gui/View/Layout/DimView.cs
+++ b/Terminal.Gui/View/Layout/DimView.cs
@@ -15,7 +15,7 @@ public class DimView : Dim
     /// </summary>
     /// <param name="view">The view the dimension is anchored to.</param>
     /// <param name="dimension">Indicates which dimension is tracked.</param>
-    public DimView (View view, Dimension dimension)
+    public DimView (View? view, Dimension dimension)
     {
         Target = view;
         Dimension = dimension;
@@ -35,7 +35,7 @@ public class DimView : Dim
     /// <summary>
     ///     Gets the View the dimension is anchored to.
     /// </summary>
-    public View Target { get; init; }
+    public View? Target { get; init; }
 
     /// <inheritdoc/>
     public override string ToString ()
diff --git a/Terminal.Gui/View/Layout/Pos.cs b/Terminal.Gui/View/Layout/Pos.cs
index 2213524ae..853bfa0ab 100644
--- a/Terminal.Gui/View/Layout/Pos.cs
+++ b/Terminal.Gui/View/Layout/Pos.cs
@@ -257,22 +257,22 @@ public abstract class Pos
     /// <summary>Creates a <see cref="Pos"/> object that tracks the Top (Y) position of the specified <see cref="View"/>.</summary>
     /// <returns>The <see cref="Pos"/> that depends on the other view.</returns>
     /// <param name="view">The <see cref="View"/>  that will be tracked.</param>
-    public static Pos Top (View view) { return new PosView (view, Side.Top); }
+    public static Pos Top (View? view) { return new PosView (view, Side.Top); }
 
     /// <summary>Creates a <see cref="Pos"/> object that tracks the Top (Y) position of the specified <see cref="View"/>.</summary>
     /// <returns>The <see cref="Pos"/> that depends on the other view.</returns>
     /// <param name="view">The <see cref="View"/>  that will be tracked.</param>
-    public static Pos Y (View view) { return new PosView (view, Side.Top); }
+    public static Pos Y (View? view) { return new PosView (view, Side.Top); }
 
     /// <summary>Creates a <see cref="Pos"/> object that tracks the Left (X) position of the specified <see cref="View"/>.</summary>
     /// <returns>The <see cref="Pos"/> that depends on the other view.</returns>
     /// <param name="view">The <see cref="View"/>  that will be tracked.</param>
-    public static Pos Left (View view) { return new PosView (view, Side.Left); }
+    public static Pos Left (View? view) { return new PosView (view, Side.Left); }
 
     /// <summary>Creates a <see cref="Pos"/> object that tracks the Left (X) position of the specified <see cref="View"/>.</summary>
     /// <returns>The <see cref="Pos"/> that depends on the other view.</returns>
     /// <param name="view">The <see cref="View"/>  that will be tracked.</param>
-    public static Pos X (View view) { return new PosView (view, Side.Left); }
+    public static Pos X (View? view) { return new PosView (view, Side.Left); }
 
     /// <summary>
     ///     Creates a <see cref="Pos"/> object that tracks the Bottom (Y+Height) coordinate of the specified
@@ -280,7 +280,7 @@ public abstract class Pos
     /// </summary>
     /// <returns>The <see cref="Pos"/> that depends on the other view.</returns>
     /// <param name="view">The <see cref="View"/>  that will be tracked.</param>
-    public static Pos Bottom (View view) { return new PosView (view, Side.Bottom); }
+    public static Pos Bottom (View? view) { return new PosView (view, Side.Bottom); }
 
     /// <summary>
     ///     Creates a <see cref="Pos"/> object that tracks the Right (X+Width) coordinate of the specified
@@ -288,7 +288,7 @@ public abstract class Pos
     /// </summary>
     /// <returns>The <see cref="Pos"/> that depends on the other view.</returns>
     /// <param name="view">The <see cref="View"/>  that will be tracked.</param>
-    public static Pos Right (View view) { return new PosView (view, Side.Right); }
+    public static Pos Right (View? view) { return new PosView (view, Side.Right); }
 
     #endregion static Pos creation methods
 
diff --git a/Terminal.Gui/View/Layout/PosView.cs b/Terminal.Gui/View/Layout/PosView.cs
index b48613307..fdf5bf784 100644
--- a/Terminal.Gui/View/Layout/PosView.cs
+++ b/Terminal.Gui/View/Layout/PosView.cs
@@ -12,12 +12,12 @@ namespace Terminal.Gui;
 /// </remarks>
 /// <param name="view">The View the position is anchored to.</param>
 /// <param name="side">The side of the View the position is anchored to.</param>
-public class PosView (View view, Side side) : Pos
+public class PosView (View? view, Side side) : Pos
 {
     /// <summary>
     ///     Gets the View the position is anchored to.
     /// </summary>
-    public View Target { get; } = view;
+    public View? Target { get; } = view;
 
     /// <summary>
     ///     Gets the side of the View the position is anchored to.
diff --git a/Terminal.Gui/View/Layout/ViewLayout.cs b/Terminal.Gui/View/Layout/ViewLayout.cs
index fa0983993..637d1f0ca 100644
--- a/Terminal.Gui/View/Layout/ViewLayout.cs
+++ b/Terminal.Gui/View/Layout/ViewLayout.cs
@@ -398,7 +398,7 @@ public partial class View
     ///     Either <see cref="Application.Top"/> (if <paramref name="viewToMove"/> does not have a Super View) or
     ///     <paramref name="viewToMove"/>'s SuperView. This can be used to ensure LayoutSubviews is called on the correct View.
     /// </returns>
-    internal static View GetLocationEnsuringFullVisibility (
+    internal static View? GetLocationEnsuringFullVisibility (
         View viewToMove,
         int targetX,
         int targetY,
@@ -408,7 +408,7 @@ public partial class View
     )
     {
         int maxDimension;
-        View superView;
+        View? superView;
         statusBar = null!;
 
         if (viewToMove?.SuperView is null || viewToMove == Application.Top || viewToMove?.SuperView == Application.Top)
diff --git a/Terminal.Gui/View/ViewDrawing.cs b/Terminal.Gui/View/ViewDrawing.cs
index 67778536f..73fa5d550 100644
--- a/Terminal.Gui/View/ViewDrawing.cs
+++ b/Terminal.Gui/View/ViewDrawing.cs
@@ -288,19 +288,19 @@ public partial class View
     public void DrawHotString (string text, Attribute hotColor, Attribute normalColor)
     {
         Rune hotkeySpec = HotKeySpecifier == (Rune)0xffff ? (Rune)'_' : HotKeySpecifier;
-        Application.Driver.SetAttribute (normalColor);
+        Application.Driver?.SetAttribute (normalColor);
 
         foreach (Rune rune in text.EnumerateRunes ())
         {
             if (rune == new Rune (hotkeySpec.Value))
             {
-                Application.Driver.SetAttribute (hotColor);
+                Application.Driver?.SetAttribute (hotColor);
 
                 continue;
             }
 
-            Application.Driver.AddRune (rune);
-            Application.Driver.SetAttribute (normalColor);
+            Application.Driver?.AddRune (rune);
+            Application.Driver?.SetAttribute (normalColor);
         }
     }
 
diff --git a/Terminal.Gui/Views/GraphView/Annotations.cs b/Terminal.Gui/Views/GraphView/Annotations.cs
index 30247d4a6..7dbc8836e 100644
--- a/Terminal.Gui/Views/GraphView/Annotations.cs
+++ b/Terminal.Gui/Views/GraphView/Annotations.cs
@@ -133,7 +133,7 @@ public class LegendAnnotation : View, IAnnotation
     {
         if (!IsInitialized)
         {
-            ColorScheme = new ColorScheme { Normal = Application.Driver.GetAttribute () };
+            ColorScheme = new ColorScheme { Normal = Application.Driver?.GetAttribute () ?? Attribute.Default};
             graph.Add (this);
         }
 
@@ -149,7 +149,7 @@ public class LegendAnnotation : View, IAnnotation
         {
             if (entry.Item1.Color.HasValue)
             {
-                Application.Driver.SetAttribute (entry.Item1.Color.Value);
+                Application.Driver?.SetAttribute (entry.Item1.Color.Value);
             }
             else
             {
@@ -166,7 +166,7 @@ public class LegendAnnotation : View, IAnnotation
             Move (1, linesDrawn);
 
             string str = TextFormatter.ClipOrPad (entry.Item2, Viewport.Width - 1);
-            Application.Driver.AddStr (str);
+            Application.Driver?.AddStr (str);
 
             linesDrawn++;
 
diff --git a/Terminal.Gui/Views/GraphView/Axis.cs b/Terminal.Gui/Views/GraphView/Axis.cs
index efff79ce9..c46938890 100644
--- a/Terminal.Gui/Views/GraphView/Axis.cs
+++ b/Terminal.Gui/Views/GraphView/Axis.cs
@@ -103,7 +103,7 @@ public class HorizontalAxis : Axis
         graph.Move (screenPosition, y);
 
         // draw the tick on the axis
-        Application.Driver.AddRune (Glyphs.TopTee);
+        Application.Driver?.AddRune (Glyphs.TopTee);
 
         // and the label text
         if (!string.IsNullOrWhiteSpace (text))
@@ -161,7 +161,7 @@ public class HorizontalAxis : Axis
             }
 
             graph.Move (graph.Viewport.Width / 2 - toRender.Length / 2, graph.Viewport.Height - 1);
-            Application.Driver.AddStr (toRender);
+            Application.Driver?.AddStr (toRender);
         }
     }
 
@@ -222,7 +222,7 @@ public class HorizontalAxis : Axis
     protected override void DrawAxisLine (GraphView graph, int x, int y)
     {
         graph.Move (x, y);
-        Application.Driver.AddRune (Glyphs.HLine);
+        Application.Driver?.AddRune (Glyphs.HLine);
     }
 
     private IEnumerable<AxisIncrementToRender> GetLabels (GraphView graph, Rectangle viewport)
@@ -298,13 +298,13 @@ public class VerticalAxis : Axis
         graph.Move (x, screenPosition);
 
         // draw the tick on the axis
-        Application.Driver.AddRune (Glyphs.RightTee);
+        Application.Driver?.AddRune (Glyphs.RightTee);
 
         // and the label text
         if (!string.IsNullOrWhiteSpace (text))
         {
             graph.Move (Math.Max (0, x - labelThickness), screenPosition);
-            Application.Driver.AddStr (text);
+            Application.Driver?.AddStr (text);
         }
     }
 
@@ -342,7 +342,7 @@ public class VerticalAxis : Axis
             for (var i = 0; i < toRender.Length; i++)
             {
                 graph.Move (0, startDrawingAtY + i);
-                Application.Driver.AddRune ((Rune)toRender [i]);
+                Application.Driver?.AddRune ((Rune)toRender [i]);
             }
         }
     }
@@ -395,7 +395,7 @@ public class VerticalAxis : Axis
     protected override void DrawAxisLine (GraphView graph, int x, int y)
     {
         graph.Move (x, y);
-        Application.Driver.AddRune (Glyphs.VLine);
+        Application.Driver?.AddRune (Glyphs.VLine);
     }
 
     private int GetAxisYEnd (GraphView graph)
diff --git a/Terminal.Gui/Views/GraphView/Series.cs b/Terminal.Gui/Views/GraphView/Series.cs
index f0974556c..f7c02e174 100644
--- a/Terminal.Gui/Views/GraphView/Series.cs
+++ b/Terminal.Gui/Views/GraphView/Series.cs
@@ -33,7 +33,7 @@ public class ScatterSeries : ISeries
     {
         if (Fill.Color.HasValue)
         {
-            Application.Driver.SetAttribute (Fill.Color.Value);
+            Application.Driver?.SetAttribute (Fill.Color.Value);
         }
 
         foreach (PointF p in Points.Where (p => graphBounds.Contains (p)))
@@ -261,7 +261,7 @@ public class BarSeries : ISeries
 
         if (adjusted.Color.HasValue)
         {
-            Application.Driver.SetAttribute (adjusted.Color.Value);
+            Application.Driver?.SetAttribute (adjusted.Color.Value);
         }
 
         graph.DrawLine (start, end, adjusted.Rune);
diff --git a/Terminal.Gui/Views/Menu/ContextMenu.cs b/Terminal.Gui/Views/Menu/ContextMenu.cs
index 8bcbc076a..f35cbdf34 100644
--- a/Terminal.Gui/Views/Menu/ContextMenu.cs
+++ b/Terminal.Gui/Views/Menu/ContextMenu.cs
@@ -144,7 +144,7 @@ public sealed class ContextMenu : IDisposable
         _container = Application.Current;
         _container.Closing += Container_Closing;
         _container.Deactivate += Container_Deactivate;
-        Rectangle frame = Application.Driver.Screen;
+        Rectangle frame = Application.Driver?.Screen ?? Rectangle.Empty;
         Point position = Position;
 
         if (Host is { })
diff --git a/Terminal.Gui/Views/RadioGroup.cs b/Terminal.Gui/Views/RadioGroup.cs
index f0dc5174b..bb2996ba4 100644
--- a/Terminal.Gui/Views/RadioGroup.cs
+++ b/Terminal.Gui/Views/RadioGroup.cs
@@ -278,7 +278,7 @@ public class RadioGroup : View, IDesignable
 
                     if (j == hotPos && i == _cursor)
                     {
-                        Application.Driver.SetAttribute (
+                        Application.Driver?.SetAttribute (
                                                          HasFocus
                                                              ? ColorScheme.HotFocus
                                                              : GetHotNormalColor ()
@@ -286,11 +286,11 @@ public class RadioGroup : View, IDesignable
                     }
                     else if (j == hotPos && i != _cursor)
                     {
-                        Application.Driver.SetAttribute (GetHotNormalColor ());
+                        Application.Driver?.SetAttribute (GetHotNormalColor ());
                     }
                     else if (HasFocus && i == _cursor)
                     {
-                        Application.Driver.SetAttribute (ColorScheme.Focus);
+                        Application.Driver?.SetAttribute (ColorScheme.Focus);
                     }
 
                     if (rune == HotKeySpecifier && j + 1 < rlRunes.Length)
@@ -300,7 +300,7 @@ public class RadioGroup : View, IDesignable
 
                         if (i == _cursor)
                         {
-                            Application.Driver.SetAttribute (
+                            Application.Driver?.SetAttribute (
                                                              HasFocus
                                                                  ? ColorScheme.HotFocus
                                                                  : GetHotNormalColor ()
@@ -308,11 +308,11 @@ public class RadioGroup : View, IDesignable
                         }
                         else if (i != _cursor)
                         {
-                            Application.Driver.SetAttribute (GetHotNormalColor ());
+                            Application.Driver?.SetAttribute (GetHotNormalColor ());
                         }
                     }
 
-                    Application.Driver.AddRune (rune);
+                    Application.Driver?.AddRune (rune);
                     Driver.SetAttribute (GetNormalColor ());
                 }
             }
diff --git a/UICatalog/Scenarios/CombiningMarks.cs b/UICatalog/Scenarios/CombiningMarks.cs
index b61ebb09f..78455eeca 100644
--- a/UICatalog/Scenarios/CombiningMarks.cs
+++ b/UICatalog/Scenarios/CombiningMarks.cs
@@ -15,20 +15,20 @@ public class CombiningMarks : Scenario
 
         top.DrawContentComplete += (s, e) =>
                                    {
-                                       Application.Driver.Move (0, 0);
-                                       Application.Driver.AddStr ("Terminal.Gui only supports combining marks that normalize. See Issue #2616.");
-                                       Application.Driver.Move (0, 2);
-                                       Application.Driver.AddStr ("\u0301\u0301\u0328<- \"\\u301\\u301\\u328]\" using AddStr.");
-                                       Application.Driver.Move (0, 3);
-                                       Application.Driver.AddStr ("[a\u0301\u0301\u0328]<- \"[a\\u301\\u301\\u328]\" using AddStr.");
-                                       Application.Driver.Move (0, 4);
-                                       Application.Driver.AddRune ('[');
-                                       Application.Driver.AddRune ('a');
-                                       Application.Driver.AddRune ('\u0301');
-                                       Application.Driver.AddRune ('\u0301');
-                                       Application.Driver.AddRune ('\u0328');
-                                       Application.Driver.AddRune (']');
-                                       Application.Driver.AddStr ("<- \"[a\\u301\\u301\\u328]\" using AddRune for each.");
+                                       Application.Driver?.Move (0, 0);
+                                       Application.Driver?.AddStr ("Terminal.Gui only supports combining marks that normalize. See Issue #2616.");
+                                       Application.Driver?.Move (0, 2);
+                                       Application.Driver?.AddStr ("\u0301\u0301\u0328<- \"\\u301\\u301\\u328]\" using AddStr.");
+                                       Application.Driver?.Move (0, 3);
+                                       Application.Driver?.AddStr ("[a\u0301\u0301\u0328]<- \"[a\\u301\\u301\\u328]\" using AddStr.");
+                                       Application.Driver?.Move (0, 4);
+                                       Application.Driver?.AddRune ('[');
+                                       Application.Driver?.AddRune ('a');
+                                       Application.Driver?.AddRune ('\u0301');
+                                       Application.Driver?.AddRune ('\u0301');
+                                       Application.Driver?.AddRune ('\u0328');
+                                       Application.Driver?.AddRune (']');
+                                       Application.Driver?.AddStr ("<- \"[a\\u301\\u301\\u328]\" using AddRune for each.");
                                    };
 
         Application.Run (top);
diff --git a/UICatalog/Scenarios/Images.cs b/UICatalog/Scenarios/Images.cs
index d31eae9cc..f17246742 100644
--- a/UICatalog/Scenarios/Images.cs
+++ b/UICatalog/Scenarios/Images.cs
@@ -20,9 +20,9 @@ public class Images : Scenario
         Application.Init ();
         var win = new Window { Title = $"{Application.QuitKey} to Quit - Scenario: {GetName()}" };
 
-        bool canTrueColor = Application.Driver.SupportsTrueColor;
+        bool canTrueColor = Application.Driver?.SupportsTrueColor ?? false;
 
-        var lblDriverName = new Label { X = 0, Y = 0, Text = $"Driver is {Application.Driver.GetType ().Name}" };
+        var lblDriverName = new Label { X = 0, Y = 0, Text = $"Driver is {Application.Driver?.GetType ().Name}" };
         win.Add (lblDriverName);
 
         var cbSupportsTrueColor = new CheckBox
diff --git a/UICatalog/Scenarios/SendKeys.cs b/UICatalog/Scenarios/SendKeys.cs
index a27a80232..6dc4a3bdf 100644
--- a/UICatalog/Scenarios/SendKeys.cs
+++ b/UICatalog/Scenarios/SendKeys.cs
@@ -86,7 +86,7 @@ public class SendKeys : Scenario
                                     ? (ConsoleKey)char.ToUpper (r)
                                     : (ConsoleKey)r;
 
-                Application.Driver.SendKeys (
+                Application.Driver?.SendKeys (
                                              r,
                                              ck,
                                              ckbShift.State == CheckState.Checked,
diff --git a/UICatalog/Scenarios/TextEffectsScenario.cs b/UICatalog/Scenarios/TextEffectsScenario.cs
index 17f6a6e5c..7d5d0e156 100644
--- a/UICatalog/Scenarios/TextEffectsScenario.cs
+++ b/UICatalog/Scenarios/TextEffectsScenario.cs
@@ -260,5 +260,5 @@ internal class GradientsView : View
         }
     }
 
-    private static void SetColor (Color color) { Application.Driver.SetAttribute (new (color, color)); }
+    private static void SetColor (Color color) { Application.Driver?.SetAttribute (new (color, color)); }
 }
diff --git a/UICatalog/Scenarios/TrueColors.cs b/UICatalog/Scenarios/TrueColors.cs
index 19e00187d..d08d9685a 100644
--- a/UICatalog/Scenarios/TrueColors.cs
+++ b/UICatalog/Scenarios/TrueColors.cs
@@ -19,11 +19,11 @@ public class TrueColors : Scenario
         var x = 2;
         var y = 1;
 
-        bool canTrueColor = Application.Driver.SupportsTrueColor;
+        bool canTrueColor = Application.Driver?.SupportsTrueColor ?? false;
 
         var lblDriverName = new Label
         {
-            X = x, Y = y++, Text = $"Current driver is {Application.Driver.GetType ().Name}"
+            X = x, Y = y++, Text = $"Current driver is {Application.Driver?.GetType ().Name}"
         };
         app.Add (lblDriverName);
         y++;
diff --git a/UICatalog/Scenarios/VkeyPacketSimulator.cs b/UICatalog/Scenarios/VkeyPacketSimulator.cs
index 50ce09b71..975775f45 100644
--- a/UICatalog/Scenarios/VkeyPacketSimulator.cs
+++ b/UICatalog/Scenarios/VkeyPacketSimulator.cs
@@ -198,7 +198,7 @@ public class VkeyPacketSimulator : Scenario
                                                            char keyChar =
                                                                ConsoleKeyMapping.EncodeKeyCharForVKPacket (consoleKeyInfo);
 
-                                                           Application.Driver.SendKeys (
+                                                           Application.Driver?.SendKeys (
                                                                                         keyChar,
                                                                                         ConsoleKey.Packet,
                                                                                         consoleKeyInfo.Modifiers.HasFlag (ConsoleModifiers.Shift),
diff --git a/UICatalog/UICatalog.cs b/UICatalog/UICatalog.cs
index ddb4c656f..dd4184cb4 100644
--- a/UICatalog/UICatalog.cs
+++ b/UICatalog/UICatalog.cs
@@ -369,7 +369,7 @@ internal class UICatalogApp
     /// </summary>
     public class UICatalogTopLevel : Toplevel
     {
-        public ListView CategoryList;
+        public ListView? CategoryList;
         public MenuItem? MiForce16Colors;
         public MenuItem? MiIsMenuBorderDisabled;
         public MenuItem? MiIsMouseDisabled;
@@ -999,7 +999,7 @@ internal class UICatalogApp
                 Title = "Force _16 Colors",
                 Shortcut = (KeyCode)Key.F6,
                 Checked = Application.Force16Colors,
-                CanExecute = () => Application.Driver.SupportsTrueColor
+                CanExecute = () => Application.Driver?.SupportsTrueColor ?? false
             };
             MiForce16Colors.CheckType |= MenuItemCheckStyle.Checked;
 
diff --git a/UnitTests/Application/ApplicationTests.cs b/UnitTests/Application/ApplicationTests.cs
index a7c1fc64a..6363233a9 100644
--- a/UnitTests/Application/ApplicationTests.cs
+++ b/UnitTests/Application/ApplicationTests.cs
@@ -44,7 +44,7 @@ public class ApplicationTests
         Toplevel top = new ();
         Application.Begin (top);
         Assert.Equal (new (0, 0, 80, 25), Application.Top.Frame);
-        ((FakeDriver)Application.Driver).SetBufferSize (5, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (5, 5);
         Assert.Equal (new (0, 0, 5, 5), Application.Top.Frame);
         top.Dispose ();
     }
@@ -134,7 +134,7 @@ public class ApplicationTests
         Application.Init (driverName: driverType.Name);
         Assert.NotNull (Application.Driver);
         Assert.NotEqual (driver, Application.Driver);
-        Assert.Equal (driverType, Application.Driver.GetType ());
+        Assert.Equal (driverType, Application.Driver?.GetType ());
         Shutdown ();
     }
 
@@ -565,8 +565,8 @@ public class ApplicationTests
         Assert.NotNull (Application.MainLoop);
 
         // FakeDriver is always 80x25
-        Assert.Equal (80, Application.Driver.Cols);
-        Assert.Equal (25, Application.Driver.Rows);
+        Assert.Equal (80, Application.Driver!.Cols);
+        Assert.Equal (25, Application.Driver!.Rows);
     }
 
     private void Pre_Init_State ()
@@ -695,7 +695,7 @@ public class ApplicationTests
         Application.ForceDriver = "FakeDriver";
 
         Application.Init ();
-        Assert.Equal (typeof (FakeDriver), Application.Driver.GetType ());
+        Assert.Equal (typeof (FakeDriver), Application.Driver?.GetType ());
 
         Application.Iteration += (s, a) => { Application.RequestStop (); };
 
@@ -737,7 +737,7 @@ public class ApplicationTests
         Application.Iteration += (s, a) => { Application.RequestStop (); };
 
         Application.Run<TestToplevel> ();
-        Assert.Equal (typeof (FakeDriver), Application.Driver.GetType ());
+        Assert.Equal (typeof (FakeDriver), Application.Driver?.GetType ());
 
         Application.Top.Dispose ();
         Shutdown ();
@@ -888,7 +888,7 @@ public class ApplicationTests
             Width = 5, Height = 5,
             Arrangement = ViewArrangement.Movable
         };
-        ((FakeDriver)Application.Driver).SetBufferSize (10, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (10, 10);
         RunState rs = Application.Begin (w);
 
         // Don't use visuals to test as style of border can change over time.
diff --git a/UnitTests/Application/CursorTests.cs b/UnitTests/Application/CursorTests.cs
index 337003b0f..87999a9d2 100644
--- a/UnitTests/Application/CursorTests.cs
+++ b/UnitTests/Application/CursorTests.cs
@@ -141,7 +141,10 @@ public class CursorTests
 
         Assert.True (view.HasFocus);
         Assert.False (Application.PositionCursor (view));
-        Application.Driver.GetCursorVisibility (out CursorVisibility cursor);
-        Assert.Equal (CursorVisibility.Invisible, cursor);
+
+        if (Application.Driver?.GetCursorVisibility (out CursorVisibility cursor) ?? false)
+        {
+            Assert.Equal (CursorVisibility.Invisible, cursor);
+        }
     }
 }
diff --git a/UnitTests/Clipboard/ClipboardTests.cs b/UnitTests/Clipboard/ClipboardTests.cs
index 65c2e7707..e2c0ac11f 100644
--- a/UnitTests/Clipboard/ClipboardTests.cs
+++ b/UnitTests/Clipboard/ClipboardTests.cs
@@ -9,14 +9,14 @@ public class ClipboardTests
     [Fact, AutoInitShutdown (useFakeClipboard: true, fakeClipboardAlwaysThrowsNotSupportedException: true)]
     public void IClipboard_GetClipBoardData_Throws_NotSupportedException ()
     {
-        var iclip = Application.Driver.Clipboard;
+        var iclip = Application.Driver?.Clipboard;
         Assert.Throws<NotSupportedException> (() => iclip.GetClipboardData ());
     }
 
     [Fact, AutoInitShutdown (useFakeClipboard: true, fakeClipboardAlwaysThrowsNotSupportedException: true)]
     public void IClipboard_SetClipBoardData_Throws_NotSupportedException ()
     {
-        var iclip = Application.Driver.Clipboard;
+        var iclip = Application.Driver?.Clipboard;
         Assert.Throws<NotSupportedException> (() => iclip.SetClipboardData ("foo"));
     }
 
diff --git a/UnitTests/ConsoleDrivers/ClipRegionTests.cs b/UnitTests/ConsoleDrivers/ClipRegionTests.cs
index 0d27f91c1..8a90f2e4d 100644
--- a/UnitTests/ConsoleDrivers/ClipRegionTests.cs
+++ b/UnitTests/ConsoleDrivers/ClipRegionTests.cs
@@ -26,8 +26,8 @@ public class ClipRegionTests
     {
         var driver = (ConsoleDriver)Activator.CreateInstance (driverType);
         Application.Init (driver);
-        Application.Driver.Rows = 25;
-        Application.Driver.Cols = 80;
+        Application.Driver!.Rows = 25;
+        Application.Driver!.Cols = 80;
 
         driver.Move (0, 0);
         driver.AddRune ('x');
@@ -94,8 +94,8 @@ public class ClipRegionTests
     {
         var driver = (ConsoleDriver)Activator.CreateInstance (driverType);
         Application.Init (driver);
-        Application.Driver.Rows = 10;
-        Application.Driver.Cols = 10;
+        Application.Driver!.Rows = 10;
+        Application.Driver!.Cols = 10;
 
         // positive
         Assert.True (driver.IsValidLocation (0, 0));
diff --git a/UnitTests/ConsoleDrivers/ConsoleDriverTests.cs b/UnitTests/ConsoleDrivers/ConsoleDriverTests.cs
index afbf20d96..8ecc97807 100644
--- a/UnitTests/ConsoleDrivers/ConsoleDriverTests.cs
+++ b/UnitTests/ConsoleDrivers/ConsoleDriverTests.cs
@@ -234,7 +234,7 @@ public class ConsoleDriverTests
     //		{
     //			var win = new Window ();
     //			Application.Begin (win);
-    //			((FakeDriver)Application.Driver).SetBufferSize (20, 8);
+    //			((FakeDriver)Application.Driver!).SetBufferSize (20, 8);
 
     //			System.Threading.Tasks.Task.Run (() => {
     //				System.Threading.Tasks.Task.Delay (500).Wait ();
diff --git a/UnitTests/ConsoleDrivers/ConsoleKeyMappingTests.cs b/UnitTests/ConsoleDrivers/ConsoleKeyMappingTests.cs
index de05b868f..1ea984b3d 100644
--- a/UnitTests/ConsoleDrivers/ConsoleKeyMappingTests.cs
+++ b/UnitTests/ConsoleDrivers/ConsoleKeyMappingTests.cs
@@ -123,7 +123,7 @@ public class ConsoleKeyMappingTests
                                          if (iterations == 0)
                                          {
                                              var keyChar = ConsoleKeyMapping.EncodeKeyCharForVKPacket (consoleKeyInfo);
-                                             Application.Driver.SendKeys (keyChar, ConsoleKey.Packet, shift, alt, control);
+                                             Application.Driver?.SendKeys (keyChar, ConsoleKey.Packet, shift, alt, control);
                                          }
                                      };
             Application.Run ();
diff --git a/UnitTests/Dialogs/MessageBoxTests.cs b/UnitTests/Dialogs/MessageBoxTests.cs
index f32f7074a..8715eea2c 100644
--- a/UnitTests/Dialogs/MessageBoxTests.cs
+++ b/UnitTests/Dialogs/MessageBoxTests.cs
@@ -125,7 +125,7 @@ public class MessageBoxTests
     public void Location_Default ()
     {
         int iterations = -1;
-        ((FakeDriver)Application.Driver).SetBufferSize (100, 100);
+        ((FakeDriver)Application.Driver!).SetBufferSize (100, 100);
 
         Application.Iteration += (s, a) =>
                                  {
@@ -243,7 +243,7 @@ public class MessageBoxTests
         int iterations = -1;
         var top = new Toplevel ();
         top.BorderStyle = LineStyle.None;
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 10);
 
         var btn =
             $"{
@@ -319,7 +319,7 @@ public class MessageBoxTests
         int iterations = -1;
         var top = new Toplevel ();
         top.BorderStyle = LineStyle.None;
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 10);
 
         var btn =
             $"{
@@ -396,7 +396,7 @@ ffffffffffffffffffff
         int iterations = -1;
         var top = new Toplevel();
         top.BorderStyle = LineStyle.None;
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 10);
 
         var btn =
             $"{
@@ -477,7 +477,7 @@ ffffffffffffffffffff
         int iterations = -1;
         var top = new Toplevel();
         top.BorderStyle = LineStyle.None;
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 10);
 
         var btn =
             $"{
@@ -547,7 +547,7 @@ ffffffffffffffffffff
     public void Size_Default ()
     {
         int iterations = -1;
-        ((FakeDriver)Application.Driver).SetBufferSize (100, 100);
+        ((FakeDriver)Application.Driver!).SetBufferSize (100, 100);
 
         Application.Iteration += (s, a) =>
                                  {
@@ -650,7 +650,7 @@ ffffffffffffffffffff
                 CM.Glyphs.RightBracket
             }";
 
-        ((FakeDriver)Application.Driver).SetBufferSize (40 + 4, 8);
+        ((FakeDriver)Application.Driver!).SetBufferSize (40 + 4, 8);
 
         Application.Iteration += (s, a) =>
                                  {
@@ -737,7 +737,7 @@ ffffffffffffffffffff
     public void Size_Not_Default_Message (int height, int width, string message)
     {
         int iterations = -1;
-        ((FakeDriver)Application.Driver).SetBufferSize (100, 100);
+        ((FakeDriver)Application.Driver!).SetBufferSize (100, 100);
 
         Application.Iteration += (s, a) =>
                                  {
@@ -774,7 +774,7 @@ ffffffffffffffffffff
     public void Size_Not_Default_Message_Button (int height, int width, string message)
     {
         int iterations = -1;
-        ((FakeDriver)Application.Driver).SetBufferSize (100, 100);
+        ((FakeDriver)Application.Driver!).SetBufferSize (100, 100);
 
         Application.Iteration += (s, a) =>
                                  {
@@ -807,7 +807,7 @@ ffffffffffffffffffff
     public void Size_Not_Default_No_Message (int height, int width)
     {
         int iterations = -1;
-        ((FakeDriver)Application.Driver).SetBufferSize (100, 100);
+        ((FakeDriver)Application.Driver!).SetBufferSize (100, 100);
 
         Application.Iteration += (s, a) =>
                                  {
diff --git a/UnitTests/Drawing/RulerTests.cs b/UnitTests/Drawing/RulerTests.cs
index 0fdbfd7e2..d43ea327f 100644
--- a/UnitTests/Drawing/RulerTests.cs
+++ b/UnitTests/Drawing/RulerTests.cs
@@ -29,7 +29,7 @@ public class RulerTests
     [AutoInitShutdown]
     public void Draw_Default ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize (25, 25);
+        ((FakeDriver)Application.Driver!).SetBufferSize (25, 25);
 
         var r = new Ruler ();
         r.Draw (Point.Empty);
@@ -47,7 +47,7 @@ public class RulerTests
         var top = new Toplevel ();
         top.Add (f);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (len + 5, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (len + 5, 5);
         Assert.Equal (new (0, 0, len + 5, 5), f.Frame);
 
         var r = new Ruler ();
@@ -121,7 +121,7 @@ public class RulerTests
         var top = new Toplevel ();
         top.Add (f);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (len + 5, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (len + 5, 5);
         Assert.Equal (new (0, 0, len + 5, 5), f.Frame);
 
         var r = new Ruler ();
@@ -168,7 +168,7 @@ public class RulerTests
         var top = new Toplevel ();
         top.Add (f);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (5, len + 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (5, len + 5);
         Assert.Equal (new (0, 0, 5, len + 5), f.Frame);
 
         var r = new Ruler ();
@@ -302,7 +302,7 @@ public class RulerTests
         var top = new Toplevel ();
         top.Add (f);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (5, len + 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (5, len + 5);
         Assert.Equal (new (0, 0, 5, len + 5), f.Frame);
 
         var r = new Ruler ();
diff --git a/UnitTests/Drawing/ThicknessTests.cs b/UnitTests/Drawing/ThicknessTests.cs
index 8215f8148..c71135722 100644
--- a/UnitTests/Drawing/ThicknessTests.cs
+++ b/UnitTests/Drawing/ThicknessTests.cs
@@ -51,13 +51,13 @@ public class ThicknessTests (ITestOutputHelper output)
     [AutoInitShutdown]
     public void DrawTests ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize (60, 60);
+        ((FakeDriver)Application.Driver!).SetBufferSize (60, 60);
         var t = new Thickness (0, 0, 0, 0);
         var r = new Rectangle (5, 5, 40, 15);
         View.Diagnostics |= ViewDiagnosticFlags.Padding;
 
-        Application.Driver.FillRect (
-                                     new Rectangle (0, 0, Application.Driver.Cols, Application.Driver.Rows),
+        Application.Driver?.FillRect (
+                                     new Rectangle (0, 0, Application.Driver!.Cols, Application.Driver!.Rows),
                                      (Rune)' '
                                     );
         t.Draw (r, "Test");
@@ -73,8 +73,8 @@ public class ThicknessTests (ITestOutputHelper output)
         r = new Rectangle (5, 5, 40, 15);
         View.Diagnostics |= ViewDiagnosticFlags.Padding;
 
-        Application.Driver.FillRect (
-                                     new Rectangle (0, 0, Application.Driver.Cols, Application.Driver.Rows),
+        Application.Driver?.FillRect (
+                                     new Rectangle (0, 0, Application.Driver!.Cols, Application.Driver!.Rows),
                                      (Rune)' '
                                     );
         t.Draw (r, "Test");
@@ -104,8 +104,8 @@ public class ThicknessTests (ITestOutputHelper output)
         r = new Rectangle (5, 5, 40, 15);
         View.Diagnostics |= ViewDiagnosticFlags.Padding;
 
-        Application.Driver.FillRect (
-                                     new Rectangle (0, 0, Application.Driver.Cols, Application.Driver.Rows),
+        Application.Driver?.FillRect (
+                                     new Rectangle (0, 0, Application.Driver!.Cols, Application.Driver!.Rows),
                                      (Rune)' '
                                     );
         t.Draw (r, "Test");
@@ -135,8 +135,8 @@ public class ThicknessTests (ITestOutputHelper output)
         r = new Rectangle (5, 5, 40, 15);
         View.Diagnostics |= ViewDiagnosticFlags.Padding;
 
-        Application.Driver.FillRect (
-                                     new Rectangle (0, 0, Application.Driver.Cols, Application.Driver.Rows),
+        Application.Driver?.FillRect (
+                                     new Rectangle (0, 0, Application.Driver!.Cols, Application.Driver!.Rows),
                                      (Rune)' '
                                     );
         t.Draw (r, "Test");
@@ -174,7 +174,7 @@ public class ThicknessTests (ITestOutputHelper output)
         top.Add (f);
         Application.Begin (top);
 
-        ((FakeDriver)Application.Driver).SetBufferSize (45, 20);
+        ((FakeDriver)Application.Driver!).SetBufferSize (45, 20);
         var t = new Thickness (0, 0, 0, 0);
         var r = new Rectangle (2, 2, 40, 15);
         Application.Refresh ();
diff --git a/UnitTests/FileServices/FileDialogTests.cs b/UnitTests/FileServices/FileDialogTests.cs
index 1395543ee..1488a75f0 100644
--- a/UnitTests/FileServices/FileDialogTests.cs
+++ b/UnitTests/FileServices/FileDialogTests.cs
@@ -701,14 +701,14 @@ public class FileDialogTests (ITestOutputHelper output)
 
     private void Send (char ch, ConsoleKey ck, bool shift = false, bool alt = false, bool control = false)
     {
-        Application.Driver.SendKeys (ch, ck, shift, alt, control);
+        Application.Driver?.SendKeys (ch, ck, shift, alt, control);
     }
 
     private void Send (string chars)
     {
         foreach (char ch in chars)
         {
-            Application.Driver.SendKeys (ch, ConsoleKey.NoName, false, false, false);
+            Application.Driver?.SendKeys (ch, ConsoleKey.NoName, false, false, false);
         }
     }
 
diff --git a/UnitTests/Text/TextFormatterTests.cs b/UnitTests/Text/TextFormatterTests.cs
index 6746f8ad7..f821d504b 100644
--- a/UnitTests/Text/TextFormatterTests.cs
+++ b/UnitTests/Text/TextFormatterTests.cs
@@ -451,7 +451,7 @@ ssb
     [SetupFakeDriver]
     public void FillRemaining_True_False ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize (22, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (22, 5);
 
         Attribute [] attrs =
         {
@@ -6041,7 +6041,7 @@ B")]
             Text = text
         };
 
-        Application.Driver.FillRect (new Rectangle (0, 0, 7, 7), (Rune)'*');
+        Application.Driver?.FillRect (new Rectangle (0, 0, 7, 7), (Rune)'*');
         tf.Draw (new Rectangle (0, 0, 7, 7), Attribute.Default, Attribute.Default);
         TestHelpers.AssertDriverContentsWithFrameAre (expectedText, _output);
     }
diff --git a/UnitTests/View/Adornment/BorderTests.cs b/UnitTests/View/Adornment/BorderTests.cs
index 387844dbe..cae90f708 100644
--- a/UnitTests/View/Adornment/BorderTests.cs
+++ b/UnitTests/View/Adornment/BorderTests.cs
@@ -95,7 +95,7 @@ public class BorderTests (ITestOutputHelper output)
         RunState rs = Application.Begin (win);
         var firstIteration = false;
 
-        ((FakeDriver)Application.Driver).SetBufferSize (width, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (width, 5);
         Application.RunIteration (ref rs, ref firstIteration);
         var expected = string.Empty;
 
@@ -229,7 +229,7 @@ public class BorderTests (ITestOutputHelper output)
         RunState rs = Application.Begin (win);
         var firstIteration = false;
 
-        ((FakeDriver)Application.Driver).SetBufferSize (width, 4);
+        ((FakeDriver)Application.Driver!).SetBufferSize (width, 4);
         Application.RunIteration (ref rs, ref firstIteration);
         var expected = string.Empty;
 
@@ -363,7 +363,7 @@ public class BorderTests (ITestOutputHelper output)
         RunState rs = Application.Begin (win);
         var firstIteration = false;
 
-        ((FakeDriver)Application.Driver).SetBufferSize (width, 4);
+        ((FakeDriver)Application.Driver!).SetBufferSize (width, 4);
         Application.RunIteration (ref rs, ref firstIteration);
         var expected = string.Empty;
 
@@ -486,7 +486,7 @@ public class BorderTests (ITestOutputHelper output)
         RunState rs = Application.Begin (win);
         var firstIteration = false;
 
-        ((FakeDriver)Application.Driver).SetBufferSize (20, height);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, height);
         Application.RunIteration (ref rs, ref firstIteration);
         var expected = string.Empty;
 
@@ -548,7 +548,7 @@ public class BorderTests (ITestOutputHelper output)
         RunState rs = Application.Begin (win);
         var firstIteration = false;
 
-        ((FakeDriver)Application.Driver).SetBufferSize (width, 3);
+        ((FakeDriver)Application.Driver!).SetBufferSize (width, 3);
         Application.RunIteration (ref rs, ref firstIteration);
         var expected = string.Empty;
 
@@ -728,7 +728,7 @@ public class BorderTests (ITestOutputHelper output)
         RunState rs = Application.Begin (top);
         var firstIteration = false;
 
-        ((FakeDriver)Application.Driver).SetBufferSize (5, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (5, 5);
         Application.RunIteration (ref rs, ref firstIteration);
 
         var expected = @"
@@ -756,7 +756,7 @@ public class BorderTests (ITestOutputHelper output)
         RunState rs = Application.Begin (top);
         var firstIteration = false;
 
-        ((FakeDriver)Application.Driver).SetBufferSize (10, 4);
+        ((FakeDriver)Application.Driver!).SetBufferSize (10, 4);
         Application.RunIteration (ref rs, ref firstIteration);
 
         var expected = @"
@@ -779,7 +779,7 @@ public class BorderTests (ITestOutputHelper output)
         RunState rs = Application.Begin (win);
         var firstIteration = false;
 
-        ((FakeDriver)Application.Driver).SetBufferSize (3, 3);
+        ((FakeDriver)Application.Driver!).SetBufferSize (3, 3);
         Application.RunIteration (ref rs, ref firstIteration);
 
         var expected = @"
diff --git a/UnitTests/View/Adornment/MarginTests.cs b/UnitTests/View/Adornment/MarginTests.cs
index 1cfe6f0d1..736a720b1 100644
--- a/UnitTests/View/Adornment/MarginTests.cs
+++ b/UnitTests/View/Adornment/MarginTests.cs
@@ -8,7 +8,7 @@ public class MarginTests (ITestOutputHelper output)
     [SetupFakeDriver]
     public void Margin_Uses_SuperView_ColorScheme ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize (5, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (5, 5);
         var view = new View { Height = 3, Width = 3 };
         view.Margin.Thickness = new (1);
 
diff --git a/UnitTests/View/Adornment/PaddingTests.cs b/UnitTests/View/Adornment/PaddingTests.cs
index 4f7bffb20..2c917572f 100644
--- a/UnitTests/View/Adornment/PaddingTests.cs
+++ b/UnitTests/View/Adornment/PaddingTests.cs
@@ -8,7 +8,7 @@ public class PaddingTests (ITestOutputHelper output)
     [SetupFakeDriver]
     public void Padding_Uses_Parent_ColorScheme ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize (5, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (5, 5);
         var view = new View { Height = 3, Width = 3 };
         view.Padding.Thickness = new (1);
 
diff --git a/UnitTests/View/DrawTests.cs b/UnitTests/View/DrawTests.cs
index 46c791ab4..52b4659f8 100644
--- a/UnitTests/View/DrawTests.cs
+++ b/UnitTests/View/DrawTests.cs
@@ -22,13 +22,13 @@ public class DrawTests (ITestOutputHelper _output)
         // Only valid location w/in Viewport is 0, 0 (view) - 2, 2 (screen)
 
         view.Move (0, 0);
-        Assert.Equal (new Point (2, 2), new Point (Application.Driver.Col, Application.Driver.Row));
+        Assert.Equal (new Point (2, 2), new Point (Application.Driver!.Col, Application.Driver!.Row));
 
         view.Move (-1, -1);
-        Assert.Equal (new Point (2, 2), new Point (Application.Driver.Col, Application.Driver.Row));
+        Assert.Equal (new Point (2, 2), new Point (Application.Driver!.Col, Application.Driver!.Row));
 
         view.Move (1, 1);
-        Assert.Equal (new Point (2, 2), new Point (Application.Driver.Col, Application.Driver.Row));
+        Assert.Equal (new Point (2, 2), new Point (Application.Driver!.Col, Application.Driver!.Row));
     }
 
     [Fact]
@@ -48,16 +48,16 @@ public class DrawTests (ITestOutputHelper _output)
         view.Draw ();
 
         // Only valid location w/in Viewport is 0, 0 (view) - 2, 2 (screen)
-        Assert.Equal ((Rune)' ', Application.Driver.Contents [2, 2].Rune);
+        Assert.Equal ((Rune)' ', Application.Driver?.Contents [2, 2].Rune);
 
         view.AddRune (0, 0, Rune.ReplacementChar);
-        Assert.Equal (Rune.ReplacementChar, Application.Driver.Contents [2, 2].Rune);
+        Assert.Equal (Rune.ReplacementChar, Application.Driver?.Contents [2, 2].Rune);
 
         view.AddRune (-1, -1, Rune.ReplacementChar);
-        Assert.Equal ((Rune)'M', Application.Driver.Contents [1, 1].Rune);
+        Assert.Equal ((Rune)'M', Application.Driver?.Contents [1, 1].Rune);
 
         view.AddRune (1, 1, Rune.ReplacementChar);
-        Assert.Equal ((Rune)'M', Application.Driver.Contents [3, 3].Rune);
+        Assert.Equal ((Rune)'M', Application.Driver?.Contents [3, 3].Rune);
 
         View.Diagnostics = ViewDiagnosticFlags.Off;
     }
@@ -250,7 +250,7 @@ public class DrawTests (ITestOutputHelper _output)
         top.Add (win);
 
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (10, 4);
+        ((FakeDriver)Application.Driver!).SetBufferSize (10, 4);
 
         const string expectedOutput = """
 
@@ -301,7 +301,7 @@ public class DrawTests (ITestOutputHelper _output)
         dg.Add (view);
         RunState rsTop = Application.Begin (top);
         RunState rsDiag = Application.Begin (dg);
-        ((FakeDriver)Application.Driver).SetBufferSize (30, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (30, 10);
 
         const string expectedOutput = """
 
@@ -354,7 +354,7 @@ public class DrawTests (ITestOutputHelper _output)
         top.Add (viewRight, viewBottom);
 
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (7, 7);
+        ((FakeDriver)Application.Driver!).SetBufferSize (7, 7);
 
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       """
@@ -394,7 +394,7 @@ public class DrawTests (ITestOutputHelper _output)
         var view = new View { Width = 2, Height = 2, BorderStyle = LineStyle.Single };
         view.BeginInit ();
         view.EndInit ();
-        view.SetRelativeLayout (Application.Driver.Screen.Size);
+        view.SetRelativeLayout (Application.Driver!.Screen.Size);
 
         Assert.Equal (new (0, 0, 2, 2), view.Frame);
         Assert.Equal (Rectangle.Empty, view.Viewport);
@@ -419,7 +419,7 @@ public class DrawTests (ITestOutputHelper _output)
         view.Border.Thickness = new Thickness (1, 1, 1, 0);
         view.BeginInit ();
         view.EndInit ();
-        view.SetRelativeLayout (Application.Driver.Screen.Size);
+        view.SetRelativeLayout (Application.Driver!.Screen.Size);
 
         Assert.Equal (new (0, 0, 2, 1), view.Frame);
         Assert.Equal (Rectangle.Empty, view.Viewport);
@@ -437,7 +437,7 @@ public class DrawTests (ITestOutputHelper _output)
         view.Border.Thickness = new Thickness (0, 1, 1, 1);
         view.BeginInit ();
         view.EndInit ();
-        view.SetRelativeLayout (Application.Driver.Screen.Size);
+        view.SetRelativeLayout (Application.Driver!.Screen.Size);
 
         Assert.Equal (new (0, 0, 1, 2), view.Frame);
         Assert.Equal (Rectangle.Empty, view.Viewport);
@@ -462,7 +462,7 @@ public class DrawTests (ITestOutputHelper _output)
         view.Border.Thickness = new Thickness (1, 1, 0, 1);
         view.BeginInit ();
         view.EndInit ();
-        view.SetRelativeLayout (Application.Driver.Screen.Size);
+        view.SetRelativeLayout (Application.Driver!.Screen.Size);
 
         Assert.Equal (new (0, 0, 1, 2), view.Frame);
         Assert.Equal (Rectangle.Empty, view.Viewport);
@@ -488,7 +488,7 @@ public class DrawTests (ITestOutputHelper _output)
 
         view.BeginInit ();
         view.EndInit ();
-        view.SetRelativeLayout (Application.Driver.Screen.Size);
+        view.SetRelativeLayout (Application.Driver!.Screen.Size);
 
         Assert.Equal (new (0, 0, 2, 1), view.Frame);
         Assert.Equal (Rectangle.Empty, view.Viewport);
@@ -561,7 +561,7 @@ public class DrawTests (ITestOutputHelper _output)
         container.Add (content);
         Toplevel top = new ();
         top.Add (container);
-        Application.Driver.Clip = container.Frame;
+        Application.Driver!.Clip = container.Frame;
         Application.Begin (top);
 
         TestHelpers.AssertDriverContentsWithFrameAre (
@@ -727,7 +727,7 @@ public class DrawTests (ITestOutputHelper _output)
 
         return;
 
-        void Top_LayoutComplete (object? sender, LayoutEventArgs e) { Application.Driver.Clip = container.Frame; }
+        void Top_LayoutComplete (object? sender, LayoutEventArgs e) { Application.Driver!.Clip = container.Frame; }
     }
 
     [Fact]
@@ -767,7 +767,7 @@ public class DrawTests (ITestOutputHelper _output)
         container.Add (content);
         Toplevel top = new ();
         top.Add (container);
-        Application.Driver.Clip = container.Frame;
+        Application.Driver!.Clip = container.Frame;
         Application.Begin (top);
 
         TestHelpers.AssertDriverContentsWithFrameAre (
@@ -889,7 +889,7 @@ public class DrawTests (ITestOutputHelper _output)
         top.Add (win);
 
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (10, 4);
+        ((FakeDriver)Application.Driver!).SetBufferSize (10, 4);
 
         var expected = """
 
@@ -928,13 +928,13 @@ public class DrawTests (ITestOutputHelper _output)
         view.Border.Thickness = new Thickness (1);
         view.BeginInit ();
         view.EndInit ();
-        Assert.Equal (view.Frame, Application.Driver.Clip);
+        Assert.Equal (view.Frame, Application.Driver?.Clip);
 
         // Act
         view.SetClip ();
 
         // Assert
-        Assert.Equal (expectedClip, Application.Driver.Clip);
+        Assert.Equal (expectedClip, Application.Driver?.Clip);
         view.Dispose ();
     }
 
@@ -960,14 +960,14 @@ public class DrawTests (ITestOutputHelper _output)
         view.Border.Thickness = new Thickness (1);
         view.BeginInit ();
         view.EndInit ();
-        Assert.Equal (view.Frame, Application.Driver.Clip);
+        Assert.Equal (view.Frame, Application.Driver?.Clip);
         view.Viewport = view.Viewport with { X = 1, Y = 1 };
 
         // Act
         view.SetClip ();
 
         // Assert
-        Assert.Equal (expectedClip, Application.Driver.Clip);
+        Assert.Equal (expectedClip, Application.Driver?.Clip);
         view.Dispose ();
     }
 
diff --git a/UnitTests/View/Layout/Dim.FillTests.cs b/UnitTests/View/Layout/Dim.FillTests.cs
index c4b4ebacf..cdda3088d 100644
--- a/UnitTests/View/Layout/Dim.FillTests.cs
+++ b/UnitTests/View/Layout/Dim.FillTests.cs
@@ -14,7 +14,7 @@ public class DimFillTests (ITestOutputHelper output)
         var top = new Toplevel ();
         top.Add (view);
         RunState rs = Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (32, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (32, 5);
 
         //view.SetNeedsLayout ();
         top.LayoutSubviews ();
diff --git a/UnitTests/View/Layout/Pos.AnchorEndTests.cs b/UnitTests/View/Layout/Pos.AnchorEndTests.cs
index 4309ee858..ddd3c62af 100644
--- a/UnitTests/View/Layout/Pos.AnchorEndTests.cs
+++ b/UnitTests/View/Layout/Pos.AnchorEndTests.cs
@@ -184,7 +184,7 @@ public class PosAnchorEndTests (ITestOutputHelper output)
     [SetupFakeDriver]
     public void  PosAnchorEnd_View_And_Button ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 5);
 
         var b = $"{CM.Glyphs.LeftBracket} Ok {CM.Glyphs.RightBracket}";
 
diff --git a/UnitTests/View/Layout/Pos.CenterTests.cs b/UnitTests/View/Layout/Pos.CenterTests.cs
index a17b1132a..e713c07b6 100644
--- a/UnitTests/View/Layout/Pos.CenterTests.cs
+++ b/UnitTests/View/Layout/Pos.CenterTests.cs
@@ -85,7 +85,7 @@ public class PosCenterTests (ITestOutputHelper output)
         RunState rs = Application.Begin (win);
         var firstIteration = false;
 
-        ((FakeDriver)Application.Driver).SetBufferSize (20, height);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, height);
         Application.RunIteration (ref rs, ref firstIteration);
         var expected = string.Empty;
 
@@ -232,7 +232,7 @@ public class PosCenterTests (ITestOutputHelper output)
         RunState rs = Application.Begin (win);
         var firstIteration = false;
 
-        ((FakeDriver)Application.Driver).SetBufferSize (width, 7);
+        ((FakeDriver)Application.Driver!).SetBufferSize (width, 7);
         Application.RunIteration (ref rs, ref firstIteration);
         var expected = string.Empty;
 
diff --git a/UnitTests/View/Layout/ViewportTests.cs b/UnitTests/View/Layout/ViewportTests.cs
index f5bc9212d..f0d30f118 100644
--- a/UnitTests/View/Layout/ViewportTests.cs
+++ b/UnitTests/View/Layout/ViewportTests.cs
@@ -472,7 +472,7 @@ public class ViewportTests (ITestOutputHelper output)
     //[InlineData (5, 5, false)]
     //public void IsVisibleInSuperView_With_Driver (int x, int y, bool expected)
     //{
-    //    ((FakeDriver)Application.Driver).SetBufferSize (10, 10);
+    //    ((FakeDriver)Application.Driver!).SetBufferSize (10, 10);
 
     //    var view = new View { X = 1, Y = 1, Width = 5, Height = 5 };
     //    var top = new Toplevel ();
diff --git a/UnitTests/View/NavigationTests.cs b/UnitTests/View/NavigationTests.cs
index 05dc30a1f..5a7019c19 100644
--- a/UnitTests/View/NavigationTests.cs
+++ b/UnitTests/View/NavigationTests.cs
@@ -669,7 +669,7 @@ public class NavigationTests (ITestOutputHelper output)
 //        Assert.False (tfQuiting);
 //        Assert.False (topQuiting);
 
-//        Application.Driver.SendKeys ('Q', ConsoleKey.Q, false, false, true);
+//        Application.Driver?.SendKeys ('Q', ConsoleKey.Q, false, false, true);
 //        Assert.False (sbQuiting);
 //        Assert.True (tfQuiting);
 //        Assert.False (topQuiting);
@@ -677,7 +677,7 @@ public class NavigationTests (ITestOutputHelper output)
 //#if BROKE_WITH_2927
 //        tf.KeyPressed -= Tf_KeyPress;
 //        tfQuiting = false;
-//        Application.Driver.SendKeys ('q', ConsoleKey.Q, false, false, true);
+//        Application.Driver?.SendKeys ('q', ConsoleKey.Q, false, false, true);
 //        Application.MainLoop.RunIteration ();
 //        Assert.True (sbQuiting);
 //        Assert.False (tfQuiting);
@@ -685,7 +685,7 @@ public class NavigationTests (ITestOutputHelper output)
 
 //        sb.RemoveItem (0);
 //        sbQuiting = false;
-//        Application.Driver.SendKeys ('q', ConsoleKey.Q, false, false, true);
+//        Application.Driver?.SendKeys ('q', ConsoleKey.Q, false, false, true);
 //        Application.MainLoop.RunIteration ();
 //        Assert.False (sbQuiting);
 //        Assert.False (tfQuiting);
@@ -733,13 +733,13 @@ public class NavigationTests (ITestOutputHelper output)
 //        Assert.False (sbQuiting);
 //        Assert.False (tfQuiting);
 
-//        Application.Driver.SendKeys ('Q', ConsoleKey.Q, false, false, true);
+//        Application.Driver?.SendKeys ('Q', ConsoleKey.Q, false, false, true);
 //        Assert.False (sbQuiting);
 //        Assert.True (tfQuiting);
 
 //        tf.KeyDown -= Tf_KeyPressed;
 //        tfQuiting = false;
-//        Application.Driver.SendKeys ('Q', ConsoleKey.Q, false, false, true);
+//        Application.Driver?.SendKeys ('Q', ConsoleKey.Q, false, false, true);
 //        Application.MainLoop.RunIteration ();
 //#if BROKE_WITH_2927
 //        Assert.True (sbQuiting);
@@ -834,7 +834,7 @@ public class NavigationTests (ITestOutputHelper output)
         Assert.Equal (new Rectangle (0, 0, View.Driver.Cols, View.Driver.Rows), top.Frame);
         Assert.Equal (new Rectangle (0, 0, 80, 25), top.Frame);
 
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 10);
         Assert.Equal (new Rectangle (0, 0, View.Driver.Cols, View.Driver.Rows), top.Frame);
         Assert.Equal (new Rectangle (0, 0, 20, 10), top.Frame);
 
@@ -984,7 +984,7 @@ public class NavigationTests (ITestOutputHelper output)
         Assert.NotEqual (new Rectangle (0, 0, View.Driver.Cols, View.Driver.Rows), top.Frame);
         Assert.Equal (new Rectangle (3, 2, 20, 10), top.Frame);
 
-        ((FakeDriver)Application.Driver).SetBufferSize (30, 20);
+        ((FakeDriver)Application.Driver!).SetBufferSize (30, 20);
         Assert.Equal (new Rectangle (0, 0, 30, 20), new Rectangle (0, 0, View.Driver.Cols, View.Driver.Rows));
         Assert.NotEqual (new Rectangle (0, 0, View.Driver.Cols, View.Driver.Rows), top.Frame);
         Assert.Equal (new Rectangle (3, 2, 20, 10), top.Frame);
diff --git a/UnitTests/View/TextTests.cs b/UnitTests/View/TextTests.cs
index 3bd6cfb23..f0cb43091 100644
--- a/UnitTests/View/TextTests.cs
+++ b/UnitTests/View/TextTests.cs
@@ -148,7 +148,7 @@ Y
         top.Add (win);
 
         RunState rs = Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (15, 15);
+        ((FakeDriver)Application.Driver!).SetBufferSize (15, 15);
 
         Assert.Equal (new (0, 0, 15, 15), win.Frame);
         Assert.Equal (new (0, 0, 15, 15), win.Margin.Frame);
@@ -416,7 +416,7 @@ Y
         var top = new Toplevel ();
         top.Add (win);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (4, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (4, 10);
 
         Assert.Equal (5, text.Length);
 
@@ -489,7 +489,7 @@ Y
         var top = new Toplevel ();
         top.Add (win);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (4, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (4, 10);
 
         Assert.Equal (5, text.Length);
         Assert.Equal (new (0, 0, 2, 5), view.Frame);
@@ -584,7 +584,7 @@ Y
         var top = new Toplevel ();
         top.Add (win);
         RunState rs = Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 20);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 20);
 
         Assert.Equal (new (0, 0, 11, 2), horizontalView.Frame);
         Assert.Equal (new (0, 3, 2, 11), verticalView.Frame);
@@ -672,7 +672,7 @@ Y
         var top = new Toplevel ();
         top.Add (win);
         RunState rs = Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (22, 22);
+        ((FakeDriver)Application.Driver!).SetBufferSize (22, 22);
 
         Assert.Equal (new (text.GetColumns (), 1), horizontalView.TextFormatter.Size);
         Assert.Equal (new (2, 8), verticalView.TextFormatter.Size);
@@ -769,7 +769,7 @@ Y
 
             for (var i = 0; i < 4; i++)
             {
-                text += Application.Driver.Contents [0, i].Rune;
+                text += Application.Driver?.Contents [0, i].Rune;
             }
 
             return text;
@@ -804,7 +804,7 @@ Y
         var top = new Toplevel ();
         top.Add (horizontalView, verticalView);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (50, 50);
+        ((FakeDriver)Application.Driver!).SetBufferSize (50, 50);
 
         Assert.Equal (new (0, 0, 12, 1), horizontalView.Frame);
         Assert.Equal (new (12, 1), horizontalView.GetSizeNeededForTextWithoutHotKey ());
@@ -900,7 +900,7 @@ Y
         var top = new Toplevel ();
         top.Add (frame);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (width + 2, 6);
+        ((FakeDriver)Application.Driver!).SetBufferSize (width + 2, 6);
 
         if (autoSize)
         {
@@ -1028,7 +1028,7 @@ Y
         var top = new Toplevel ();
         top.Add (frame);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (9, height + 2);
+        ((FakeDriver)Application.Driver!).SetBufferSize (9, height + 2);
 
         if (autoSize)
         {
@@ -1272,7 +1272,7 @@ Y
     [SetupFakeDriver]
     public void Narrow_Wide_Runes ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize (32, 32);
+        ((FakeDriver)Application.Driver!).SetBufferSize (32, 32);
         var top = new View { Width = 32, Height = 32 };
 
         var text = $"First line{Environment.NewLine}Second line";
diff --git a/UnitTests/View/ViewTests.cs b/UnitTests/View/ViewTests.cs
index 4044507f1..d545cdc1d 100644
--- a/UnitTests/View/ViewTests.cs
+++ b/UnitTests/View/ViewTests.cs
@@ -14,26 +14,26 @@ public class ViewTests (ITestOutputHelper output)
 
         view.DrawContent += (s, e) =>
                             {
-                                Rectangle savedClip = Application.Driver.Clip;
-                                Application.Driver.Clip = new (1, 1, view.Viewport.Width, view.Viewport.Height);
+                                Rectangle savedClip = Application.Driver!.Clip;
+                                Application.Driver!.Clip = new (1, 1, view.Viewport.Width, view.Viewport.Height);
 
                                 for (var row = 0; row < view.Viewport.Height; row++)
                                 {
-                                    Application.Driver.Move (1, row + 1);
+                                    Application.Driver?.Move (1, row + 1);
 
                                     for (var col = 0; col < view.Viewport.Width; col++)
                                     {
-                                        Application.Driver.AddStr ($"{col}");
+                                        Application.Driver?.AddStr ($"{col}");
                                     }
                                 }
 
-                                Application.Driver.Clip = savedClip;
+                                Application.Driver!.Clip = savedClip;
                                 e.Cancel = true;
                             };
         var top = new Toplevel ();
         top.Add (view);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 10);
 
         var expected = @"
 ┌──────────────────┐
@@ -78,26 +78,26 @@ public class ViewTests (ITestOutputHelper output)
 
         view.DrawContent += (s, e) =>
                             {
-                                Rectangle savedClip = Application.Driver.Clip;
-                                Application.Driver.Clip = new (1, 1, view.Viewport.Width, view.Viewport.Height);
+                                Rectangle savedClip = Application.Driver!.Clip;
+                                Application.Driver!.Clip = new (1, 1, view.Viewport.Width, view.Viewport.Height);
 
                                 for (var row = 0; row < view.Viewport.Height; row++)
                                 {
-                                    Application.Driver.Move (1, row + 1);
+                                    Application.Driver?.Move (1, row + 1);
 
                                     for (var col = 0; col < view.Viewport.Width; col++)
                                     {
-                                        Application.Driver.AddStr ($"{col}");
+                                        Application.Driver?.AddStr ($"{col}");
                                     }
                                 }
 
-                                Application.Driver.Clip = savedClip;
+                                Application.Driver!.Clip = savedClip;
                                 e.Cancel = true;
                             };
         var top = new Toplevel ();
         top.Add (view);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 10);
 
         var expected = @"
 ┌──────────────────┐
@@ -1016,7 +1016,7 @@ At 0,0
         view.Height = Dim.Auto ();
         Assert.Equal ("Testing visibility.".Length, view.Frame.Width);
         Assert.True (view.Visible);
-        ((FakeDriver)Application.Driver).SetBufferSize (30, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (30, 5);
 
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       @"
@@ -1107,9 +1107,9 @@ At 0,0
             Cell [,] contents = ((FakeDriver)Application.Driver).Contents;
             var runesCount = 0;
 
-            for (var i = 0; i < Application.Driver.Rows; i++)
+            for (var i = 0; i < Application.Driver!.Rows; i++)
             {
-                for (var j = 0; j < Application.Driver.Cols; j++)
+                for (var j = 0; j < Application.Driver!.Cols; j++)
                 {
                     if (contents [i, j].Rune != (Rune)' ')
                     {
diff --git a/UnitTests/Views/AppendAutocompleteTests.cs b/UnitTests/Views/AppendAutocompleteTests.cs
index fab9ca750..eaabc43a6 100644
--- a/UnitTests/Views/AppendAutocompleteTests.cs
+++ b/UnitTests/Views/AppendAutocompleteTests.cs
@@ -11,14 +11,14 @@ public class AppendAutocompleteTests (ITestOutputHelper output)
         TextField tf = GetTextFieldsInViewSuggesting ("fish");
 
         // f is typed and suggestion is "fish"
-        Application.Driver.SendKeys ('f', ConsoleKey.F, false, false, false);
+        Application.Driver?.SendKeys ('f', ConsoleKey.F, false, false, false);
         tf.Draw ();
         tf.PositionCursor ();
         TestHelpers.AssertDriverContentsAre ("fish", output);
         Assert.Equal ("f", tf.Text);
 
         // When cancelling autocomplete
-        Application.Driver.SendKeys ('e', ConsoleKey.Escape, false, false, false);
+        Application.Driver?.SendKeys ('e', ConsoleKey.Escape, false, false, false);
 
         // Suggestion should disappear
         tf.Draw ();
@@ -29,7 +29,7 @@ public class AppendAutocompleteTests (ITestOutputHelper output)
         Assert.Same (tf, Application.Top.Focused);
 
         // But can tab away
-        Application.Driver.SendKeys ('\t', ConsoleKey.Tab, false, false, false);
+        Application.Driver?.SendKeys ('\t', ConsoleKey.Tab, false, false, false);
         Assert.NotSame (tf, Application.Top.Focused);
         Application.Top.Dispose ();
     }
@@ -41,14 +41,14 @@ public class AppendAutocompleteTests (ITestOutputHelper output)
         TextField tf = GetTextFieldsInViewSuggesting ("fish");
 
         // f is typed and suggestion is "fish"
-        Application.Driver.SendKeys ('f', ConsoleKey.F, false, false, false);
+        Application.Driver?.SendKeys ('f', ConsoleKey.F, false, false, false);
         tf.Draw ();
         tf.PositionCursor ();
         TestHelpers.AssertDriverContentsAre ("fish", output);
         Assert.Equal ("f", tf.Text);
 
         // When cancelling autocomplete
-        Application.Driver.SendKeys ('\0', ConsoleKey.Escape, false, false, false);
+        Application.Driver?.SendKeys ('\0', ConsoleKey.Escape, false, false, false);
 
         // Suggestion should disappear
         tf.Draw ();
@@ -56,7 +56,7 @@ public class AppendAutocompleteTests (ITestOutputHelper output)
         Assert.Equal ("f", tf.Text);
 
         // Should reappear when you press next letter
-        Application.Driver.SendKeys ('i', ConsoleKey.I, false, false, false);
+        Application.Driver?.SendKeys ('i', ConsoleKey.I, false, false, false);
         tf.Draw ();
         tf.PositionCursor ();
         TestHelpers.AssertDriverContentsAre ("fish", output);
@@ -73,14 +73,14 @@ public class AppendAutocompleteTests (ITestOutputHelper output)
         TextField tf = GetTextFieldsInViewSuggesting ("fish", "friend");
 
         // f is typed and suggestion is "fish"
-        Application.Driver.SendKeys ('f', ConsoleKey.F, false, false, false);
+        Application.Driver?.SendKeys ('f', ConsoleKey.F, false, false, false);
         tf.Draw ();
         tf.PositionCursor ();
         TestHelpers.AssertDriverContentsAre ("fish", output);
         Assert.Equal ("f", tf.Text);
 
         // When cycling autocomplete
-        Application.Driver.SendKeys (' ', cycleKey, false, false, false);
+        Application.Driver?.SendKeys (' ', cycleKey, false, false, false);
 
         tf.Draw ();
         tf.PositionCursor ();
@@ -88,7 +88,7 @@ public class AppendAutocompleteTests (ITestOutputHelper output)
         Assert.Equal ("f", tf.Text);
 
         // Should be able to cycle in circles endlessly
-        Application.Driver.SendKeys (' ', cycleKey, false, false, false);
+        Application.Driver?.SendKeys (' ', cycleKey, false, false, false);
         tf.Draw ();
         tf.PositionCursor ();
         TestHelpers.AssertDriverContentsAre ("fish", output);
@@ -103,15 +103,15 @@ public class AppendAutocompleteTests (ITestOutputHelper output)
         TextField tf = GetTextFieldsInViewSuggesting ("fish");
 
         // f is typed and suggestion is "fish"
-        Application.Driver.SendKeys ('f', ConsoleKey.F, false, false, false);
+        Application.Driver?.SendKeys ('f', ConsoleKey.F, false, false, false);
         tf.Draw ();
         tf.PositionCursor ();
         TestHelpers.AssertDriverContentsAre ("fish", output);
         Assert.Equal ("f", tf.Text);
 
         // add a space then go back 1
-        Application.Driver.SendKeys (' ', ConsoleKey.Spacebar, false, false, false);
-        Application.Driver.SendKeys ('<', ConsoleKey.LeftArrow, false, false, false);
+        Application.Driver?.SendKeys (' ', ConsoleKey.Spacebar, false, false, false);
+        Application.Driver?.SendKeys ('<', ConsoleKey.LeftArrow, false, false, false);
 
         tf.Draw ();
         TestHelpers.AssertDriverContentsAre ("f", output);
@@ -126,14 +126,14 @@ public class AppendAutocompleteTests (ITestOutputHelper output)
         TextField tf = GetTextFieldsInViewSuggesting ("fish");
 
         // f is typed and suggestion is "fish"
-        Application.Driver.SendKeys ('f', ConsoleKey.F, false, false, false);
+        Application.Driver?.SendKeys ('f', ConsoleKey.F, false, false, false);
         tf.Draw ();
         tf.PositionCursor ();
         TestHelpers.AssertDriverContentsAre ("fish", output);
         Assert.Equal ("f", tf.Text);
 
         // x is typed and suggestion should disappear
-        Application.Driver.SendKeys ('x', ConsoleKey.X, false, false, false);
+        Application.Driver?.SendKeys ('x', ConsoleKey.X, false, false, false);
         tf.Draw ();
         TestHelpers.AssertDriverContentsAre ("fx", output);
         Assert.Equal ("fx", tf.Text);
@@ -166,7 +166,7 @@ public class AppendAutocompleteTests (ITestOutputHelper output)
         Assert.Equal ("my f", tf.Text);
 
         // When tab completing the case of the whole suggestion should be applied
-        Application.Driver.SendKeys ('\t', ConsoleKey.Tab, false, false, false);
+        Application.Driver?.SendKeys ('\t', ConsoleKey.Tab, false, false, false);
         tf.Draw ();
         TestHelpers.AssertDriverContentsAre ("my FISH", output);
         Assert.Equal ("my FISH", tf.Text);
@@ -194,7 +194,7 @@ public class AppendAutocompleteTests (ITestOutputHelper output)
         TestHelpers.AssertDriverContentsAre ("fish", output);
         Assert.Equal ("f", tf.Text);
 
-        Application.Driver.SendKeys ('\t', ConsoleKey.Tab, false, false, false);
+        Application.Driver?.SendKeys ('\t', ConsoleKey.Tab, false, false, false);
 
         tf.Draw ();
         TestHelpers.AssertDriverContentsAre ("fish", output);
@@ -204,7 +204,7 @@ public class AppendAutocompleteTests (ITestOutputHelper output)
         Assert.Same (tf, Application.Top.Focused);
 
         // Second tab should move focus (nothing to autocomplete)
-        Application.Driver.SendKeys ('\t', ConsoleKey.Tab, false, false, false);
+        Application.Driver?.SendKeys ('\t', ConsoleKey.Tab, false, false, false);
         Assert.NotSame (tf, Application.Top.Focused);
         Application.Top.Dispose ();
     }
@@ -219,7 +219,7 @@ public class AppendAutocompleteTests (ITestOutputHelper output)
         TextField tf = GetTextFieldsInViewSuggesting (overspillUsing);
 
         // f is typed we should only see 'f' up to size of View (10)
-        Application.Driver.SendKeys ('f', ConsoleKey.F, false, false, false);
+        Application.Driver?.SendKeys ('f', ConsoleKey.F, false, false, false);
         tf.Draw ();
         tf.PositionCursor ();
         TestHelpers.AssertDriverContentsAre (expectRender, output);
diff --git a/UnitTests/Views/ButtonTests.cs b/UnitTests/Views/ButtonTests.cs
index 4ef86d387..d5bc04e07 100644
--- a/UnitTests/Views/ButtonTests.cs
+++ b/UnitTests/Views/ButtonTests.cs
@@ -224,7 +224,7 @@ public class ButtonTests (ITestOutputHelper output)
         Assert.Equal ('_', btn.HotKeySpecifier.Value);
         Assert.True (btn.CanFocus);
 
-        Application.Driver.ClearContents ();
+        Application.Driver?.ClearContents ();
         btn.Draw ();
 
         expected = @$"
@@ -563,7 +563,7 @@ public class ButtonTests (ITestOutputHelper output)
         Assert.False (btn.IsInitialized);
 
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (30, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (30, 5);
 
         Assert.True (btn.IsInitialized);
         Assert.Equal ("Say Hello 你", btn.Text);
@@ -597,7 +597,7 @@ public class ButtonTests (ITestOutputHelper output)
         Assert.False (btn.IsInitialized);
 
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (30, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (30, 5);
 
         Assert.True (btn.IsInitialized);
         Assert.Equal ("Say Hello 你", btn.Text);
diff --git a/UnitTests/Views/CheckBoxTests.cs b/UnitTests/Views/CheckBoxTests.cs
index c7739272d..da41ec55a 100644
--- a/UnitTests/Views/CheckBoxTests.cs
+++ b/UnitTests/Views/CheckBoxTests.cs
@@ -254,7 +254,7 @@ public class CheckBoxTests (ITestOutputHelper output)
         top.Add (win);
 
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (30, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (30, 5);
 
         Assert.Equal (Alignment.Center, checkBox.TextAlignment);
         Assert.Equal (new (1, 1, 25, 1), checkBox.Frame);
@@ -314,7 +314,7 @@ public class CheckBoxTests (ITestOutputHelper output)
         top.Add (win);
 
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (30, 6);
+        ((FakeDriver)Application.Driver!).SetBufferSize (30, 6);
 
         Assert.Equal (Alignment.Fill, checkBox1.TextAlignment);
         Assert.Equal (new (1, 1, 25, 1), checkBox1.Frame);
@@ -372,7 +372,7 @@ public class CheckBoxTests (ITestOutputHelper output)
         top.Add (win);
 
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (30, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (30, 5);
 
         Assert.Equal (Alignment.Start, checkBox.TextAlignment);
         Assert.Equal (new (1, 1, 25, 1), checkBox.Frame);
@@ -423,7 +423,7 @@ public class CheckBoxTests (ITestOutputHelper output)
         top.Add (win);
 
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (30, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (30, 5);
 
         Assert.Equal (Alignment.End, checkBox.TextAlignment);
         Assert.Equal (new (1, 1, 25, 1), checkBox.Frame);
diff --git a/UnitTests/Views/ContextMenuTests.cs b/UnitTests/Views/ContextMenuTests.cs
index 6d42add38..efeb709fb 100644
--- a/UnitTests/Views/ContextMenuTests.cs
+++ b/UnitTests/Views/ContextMenuTests.cs
@@ -117,9 +117,9 @@ public class ContextMenuTests (ITestOutputHelper output)
     [AutoInitShutdown]
     public void Draw_A_ContextMenu_Over_A_Borderless_Top ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 15);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 15);
 
-        Assert.Equal (new Rectangle (0, 0, 20, 15), Application.Driver.Clip);
+        Assert.Equal (new Rectangle (0, 0, 20, 15), Application.Driver?.Clip);
         TestHelpers.AssertDriverContentsWithFrameAre ("", output);
 
         var top = new Toplevel { X = 2, Y = 2, Width = 15, Height = 4 };
@@ -167,7 +167,7 @@ public class ContextMenuTests (ITestOutputHelper output)
         var win = new Window ();
         top.Add (win);
         RunState rsTop = Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 15);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 15);
 
         Assert.Equal (new Rectangle (0, 0, 20, 15), win.Frame);
 
@@ -252,9 +252,9 @@ public class ContextMenuTests (ITestOutputHelper output)
     [AutoInitShutdown]
     public void Draw_A_ContextMenu_Over_A_Top_Dialog ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 15);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 15);
 
-        Assert.Equal (new Rectangle (0, 0, 20, 15), Application.Driver.Clip);
+        Assert.Equal (new Rectangle (0, 0, 20, 15), Application.Driver?.Clip);
         TestHelpers.AssertDriverContentsWithFrameAre ("", output);
 
         // Don't use Dialog here as it has more layout logic. Use Window instead.
@@ -542,7 +542,7 @@ public class ContextMenuTests (ITestOutputHelper output)
                                                       output
                                                      );
 
-        ((FakeDriver)Application.Driver).SetBufferSize (40, 20);
+        ((FakeDriver)Application.Driver!).SetBufferSize (40, 20);
         cm.Position = new Point (41, -2);
         cm.Show ();
         Application.Refresh ();
@@ -677,7 +677,7 @@ public class ContextMenuTests (ITestOutputHelper output)
                                                       output
                                                      );
 
-        ((FakeDriver)Application.Driver).SetBufferSize (18, 8);
+        ((FakeDriver)Application.Driver!).SetBufferSize (18, 8);
         cm.Position = new Point (19, 10);
         cm.Show ();
         Application.Refresh ();
@@ -891,7 +891,7 @@ public class ContextMenuTests (ITestOutputHelper output)
     [AutoInitShutdown]
     public void Show_Display_At_Zero_If_The_Toplevel_Height_Is_Less_Than_The_Menu_Height ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize (80, 3);
+        ((FakeDriver)Application.Driver!).SetBufferSize (80, 3);
 
         var cm = new ContextMenu
         {
@@ -929,7 +929,7 @@ public class ContextMenuTests (ITestOutputHelper output)
     [AutoInitShutdown]
     public void Show_Display_At_Zero_If_The_Toplevel_Width_Is_Less_Than_The_Menu_Width ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize (5, 25);
+        ((FakeDriver)Application.Driver!).SetBufferSize (5, 25);
 
         var cm = new ContextMenu
         {
diff --git a/UnitTests/Views/FrameViewTests.cs b/UnitTests/Views/FrameViewTests.cs
index 056b45747..88a5c786c 100644
--- a/UnitTests/Views/FrameViewTests.cs
+++ b/UnitTests/Views/FrameViewTests.cs
@@ -37,7 +37,7 @@ public class FrameViewTests (ITestOutputHelper output)
     [AutoInitShutdown]
     public void Draw_Defaults ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize (10, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (10, 10);
         var fv = new FrameView ();
         Assert.Equal (string.Empty, fv.Title);
         Assert.Equal (string.Empty, fv.Text);
diff --git a/UnitTests/Views/LabelTests.cs b/UnitTests/Views/LabelTests.cs
index 24a19c77d..78ed678a8 100644
--- a/UnitTests/Views/LabelTests.cs
+++ b/UnitTests/Views/LabelTests.cs
@@ -97,7 +97,7 @@ public class LabelTests (ITestOutputHelper output)
         top.Add (win);
 
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (30, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (30, 5);
 
         var expected = @"
 ┌────────────────────────────┐
@@ -137,7 +137,7 @@ public class LabelTests (ITestOutputHelper output)
         top.Add (win);
 
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (30, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (30, 5);
 
         var expected = @"
 ┌────────────────────────────┐
@@ -179,7 +179,7 @@ public class LabelTests (ITestOutputHelper output)
         label.Text = "Say Hello 你";
 
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (30, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (30, 5);
 
         var expected = @"
 ┌────────────────────────────┐
@@ -414,7 +414,7 @@ e
         Assert.False (label.IsInitialized);
 
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (30, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (30, 5);
 
         Assert.True (label.IsInitialized);
         Assert.Equal ("Say Hello 你", label.Text);
@@ -446,7 +446,7 @@ e
         Assert.False (label.IsInitialized);
 
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (30, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (30, 5);
 
         Assert.True (label.IsInitialized);
         Assert.Equal ("Say Hello 你", label.Text);
@@ -473,7 +473,7 @@ e
         var label = new Label { BorderStyle = LineStyle.Single, Text = "Test" };
         label.BeginInit ();
         label.EndInit ();
-        label.SetRelativeLayout (Application.Driver.Screen.Size);
+        label.SetRelativeLayout (Application.Driver!.Screen.Size);
 
         Assert.Equal (new (0, 0, 4, 1), label.Viewport);
         Assert.Equal (new (0, 0, 6, 3), label.Frame);
@@ -881,7 +881,7 @@ e
         Toplevel top = new ();
         top.Add (win);
         RunState rs = Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (40, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (40, 10);
 
         Assert.Equal (29, label.Text.Length);
         Assert.Equal (new (0, 0, 40, 10), top.Frame);
@@ -931,7 +931,7 @@ e
         Toplevel top = new ();
         top.Add (win);
         RunState rs = Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (40, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (40, 10);
 
         Assert.Equal (new (0, 0, 40, 10), top.Frame);
         Assert.Equal (new (0, 0, 40, 10), win.Frame);
@@ -1071,7 +1071,7 @@ e
                          {
                              if (k.KeyCode == KeyCode.Enter)
                              {
-                                 ((FakeDriver)Application.Driver).SetBufferSize (22, count + 4);
+                                 ((FakeDriver)Application.Driver!).SetBufferSize (22, count + 4);
                                  Rectangle pos = TestHelpers.AssertDriverContentsWithFrameAre (expecteds [count], output);
                                  Assert.Equal (new (0, 0, 22, count + 4), pos);
 
@@ -1135,7 +1135,7 @@ e
     [SetupFakeDriver]
     public void Label_Height_Zero_Stays_Zero ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize (10, 4);
+        ((FakeDriver)Application.Driver!).SetBufferSize (10, 4);
         var text = "Label";
 
         var label = new Label
@@ -1223,7 +1223,7 @@ e
                          {
                              if (k.KeyCode == KeyCode.Enter)
                              {
-                                 ((FakeDriver)Application.Driver).SetBufferSize (22, count + 4);
+                                 ((FakeDriver)Application.Driver!).SetBufferSize (22, count + 4);
                                  Rectangle pos = TestHelpers.AssertDriverContentsWithFrameAre (expecteds [count], output);
                                  Assert.Equal (new (0, 0, 22, count + 4), pos);
 
@@ -1299,7 +1299,7 @@ e
         var top = new Toplevel ();
         top.Add (win);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (10, 4);
+        ((FakeDriver)Application.Driver!).SetBufferSize (10, 4);
 
         Assert.Equal (5, text.Length);
         Assert.Equal (new (0, 0, 5, 1), label.Frame);
@@ -1358,7 +1358,7 @@ e
         var top = new Toplevel ();
         top.Add (win);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (10, 4);
+        ((FakeDriver)Application.Driver!).SetBufferSize (10, 4);
 
         Assert.Equal (5, text.Length);
         Assert.Equal (new (0, 0, 5, 1), label.Frame);
diff --git a/UnitTests/Views/ListViewTests.cs b/UnitTests/Views/ListViewTests.cs
index 2682fb677..049c5f7e1 100644
--- a/UnitTests/Views/ListViewTests.cs
+++ b/UnitTests/Views/ListViewTests.cs
@@ -55,7 +55,7 @@ public class ListViewTests (ITestOutputHelper output)
         var top = new Toplevel ();
         top.Add (win);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (12, 12);
+        ((FakeDriver)Application.Driver!).SetBufferSize (12, 12);
         Application.Refresh ();
 
         Assert.Equal (-1, lv.SelectedItem);
@@ -357,7 +357,7 @@ Item 6",
 
             for (var i = 0; i < 7; i++)
             {
-                item += Application.Driver.Contents [line, i].Rune;
+                item += Application.Driver?.Contents [line, i].Rune;
             }
 
             return item;
diff --git a/UnitTests/Views/MenuBarTests.cs b/UnitTests/Views/MenuBarTests.cs
index f7804dd42..35d08beff 100644
--- a/UnitTests/Views/MenuBarTests.cs
+++ b/UnitTests/Views/MenuBarTests.cs
@@ -366,7 +366,7 @@ public class MenuBarTests (ITestOutputHelper output)
         var win = new Window ();
         top.Add (win);
         RunState rsTop = Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (40, 15);
+        ((FakeDriver)Application.Driver!).SetBufferSize (40, 15);
 
         Assert.Equal (new (0, 0, 40, 15), win.Frame);
 
@@ -556,7 +556,7 @@ public class MenuBarTests (ITestOutputHelper output)
             Assert.Equal (items [i], menu.Menus [0].Title);
         }
 
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 15);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 15);
         menu.OpenMenu ();
         firstIteration = false;
         Application.RunIteration (ref rsDialog, ref firstIteration);
@@ -590,9 +590,9 @@ public class MenuBarTests (ITestOutputHelper output)
     [AutoInitShutdown]
     public void Draw_A_Menu_Over_A_Top_Dialog ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize (40, 15);
+        ((FakeDriver)Application.Driver!).SetBufferSize (40, 15);
 
-        Assert.Equal (new (0, 0, 40, 15), Application.Driver.Clip);
+        Assert.Equal (new (0, 0, 40, 15), Application.Driver?.Clip);
         TestHelpers.AssertDriverContentsWithFrameAre (@"", output);
 
         List<string> items = new ()
@@ -734,7 +734,7 @@ public class MenuBarTests (ITestOutputHelper output)
             Assert.Equal (items [i], menu.Menus [0].Title);
         }
 
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 15);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 15);
         menu.OpenMenu ();
         firstIteration = false;
         Application.RunIteration (ref rs, ref firstIteration);
@@ -805,7 +805,7 @@ public class MenuBarTests (ITestOutputHelper output)
 
         menu.CloseAllMenus ();
         menu.Frame = new (0, 0, menu.Frame.Width, menu.Frame.Height);
-        ((FakeDriver)Application.Driver).SetBufferSize (7, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (7, 5);
         menu.OpenMenu ();
         Application.Refresh ();
 
@@ -821,7 +821,7 @@ public class MenuBarTests (ITestOutputHelper output)
 
         menu.CloseAllMenus ();
         menu.Frame = new (0, 0, menu.Frame.Width, menu.Frame.Height);
-        ((FakeDriver)Application.Driver).SetBufferSize (7, 3);
+        ((FakeDriver)Application.Driver!).SetBufferSize (7, 3);
         menu.OpenMenu ();
         Application.Refresh ();
 
@@ -878,7 +878,7 @@ wo
 
         menu.CloseAllMenus ();
         menu.Frame = new (0, 0, menu.Frame.Width, menu.Frame.Height);
-        ((FakeDriver)Application.Driver).SetBufferSize (3, 2);
+        ((FakeDriver)Application.Driver!).SetBufferSize (3, 2);
         menu.OpenMenu ();
         Application.Refresh ();
 
@@ -891,7 +891,7 @@ wo
 
         menu.CloseAllMenus ();
         menu.Frame = new (0, 0, menu.Frame.Width, menu.Frame.Height);
-        ((FakeDriver)Application.Driver).SetBufferSize (3, 1);
+        ((FakeDriver)Application.Driver!).SetBufferSize (3, 1);
         menu.OpenMenu ();
         Application.Refresh ();
 
@@ -1519,7 +1519,7 @@ wo
         Toplevel top = new ();
         top.Add (win);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (40, 8);
+        ((FakeDriver)Application.Driver!).SetBufferSize (40, 8);
 
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       @"
@@ -1630,7 +1630,7 @@ wo
 
         Application.Iteration += (s, a) =>
                                  {
-                                     ((FakeDriver)Application.Driver).SetBufferSize (40, 8);
+                                     ((FakeDriver)Application.Driver!).SetBufferSize (40, 8);
 
                                      TestHelpers.AssertDriverContentsWithFrameAre (
                                                                                    @"
@@ -1741,7 +1741,7 @@ wo
             ]
         };
         win.Add (menu);
-        ((FakeDriver)Application.Driver).SetBufferSize (40, 8);
+        ((FakeDriver)Application.Driver!).SetBufferSize (40, 8);
         Application.Begin (win);
 
         TestHelpers.AssertDriverContentsWithFrameAre (
@@ -1827,7 +1827,7 @@ wo
     [AutoInitShutdown]
     public void MenuBar_In_Window_Without_Other_Views_Without_Top_Init_With_Run_T ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize (40, 8);
+        ((FakeDriver)Application.Driver!).SetBufferSize (40, 8);
 
         Application.Iteration += (s, a) =>
                                  {
@@ -2758,7 +2758,7 @@ Edit
                                                       output
                                                      );
 
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 15);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 15);
         firstIteration = false;
         Application.RunIteration (ref rs, ref firstIteration);
 
diff --git a/UnitTests/Views/OverlappedTests.cs b/UnitTests/Views/OverlappedTests.cs
index 9c7202d68..5ca0fc566 100644
--- a/UnitTests/Views/OverlappedTests.cs
+++ b/UnitTests/Views/OverlappedTests.cs
@@ -881,7 +881,7 @@ public class OverlappedTests
         var overlapped = new Overlapped ();
         var win1 = new Window { Width = 5, Height = 5, Visible = false };
         var win2 = new Window { X = 1, Y = 1, Width = 5, Height = 5 };
-        ((FakeDriver)Application.Driver).SetBufferSize (10, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (10, 10);
         RunState rsOverlapped = Application.Begin (overlapped);
 
         // Need to fool MainLoop into thinking it's running
diff --git a/UnitTests/Views/RadioGroupTests.cs b/UnitTests/Views/RadioGroupTests.cs
index 75aab7b18..4c828f2c1 100644
--- a/UnitTests/Views/RadioGroupTests.cs
+++ b/UnitTests/Views/RadioGroupTests.cs
@@ -219,7 +219,7 @@ public class RadioGroupTests (ITestOutputHelper output)
         top.Add (win);
 
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (30, 5);
+        ((FakeDriver)Application.Driver!).SetBufferSize (30, 5);
 
         Assert.Equal (Orientation.Vertical, rg.Orientation);
         Assert.Equal (2, rg.RadioLabels.Length);
diff --git a/UnitTests/Views/ScrollBarViewTests.cs b/UnitTests/Views/ScrollBarViewTests.cs
index f3f9f7c24..15c463d78 100644
--- a/UnitTests/Views/ScrollBarViewTests.cs
+++ b/UnitTests/Views/ScrollBarViewTests.cs
@@ -173,7 +173,7 @@ public class ScrollBarViewTests
         super.Add (vert);
 
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (width, height);
+        ((FakeDriver)Application.Driver!).SetBufferSize (width, height);
 
         var expected = @"
 ┌─┐
@@ -703,7 +703,7 @@ This is a test
         var sbv = new ScrollBarView { Id = "sbv", Size = width * 2, ShowScrollIndicator = true };
         super.Add (sbv);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (width, height);
+        ((FakeDriver)Application.Driver!).SetBufferSize (width, height);
 
         var expected = @"
 ┌──────────────────────────────────────┐
@@ -829,7 +829,7 @@ This is a test
         top.Add (win);
 
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (45, 20);
+        ((FakeDriver)Application.Driver!).SetBufferSize (45, 20);
 
         Assert.True (scrollBar.AutoHideScrollBars);
         Assert.False (scrollBar.ShowScrollIndicator);
@@ -867,7 +867,7 @@ This is a test
         Assert.Equal (new Rectangle (0, 0, 45, 20), pos);
 
         textView.WordWrap = true;
-        ((FakeDriver)Application.Driver).SetBufferSize (26, 20);
+        ((FakeDriver)Application.Driver!).SetBufferSize (26, 20);
         Application.Refresh ();
 
         Assert.True (textView.WordWrap);
@@ -904,7 +904,7 @@ This is a test
         pos = TestHelpers.AssertDriverContentsWithFrameAre (expected, _output);
         Assert.Equal (new Rectangle (0, 0, 26, 20), pos);
 
-        ((FakeDriver)Application.Driver).SetBufferSize (10, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (10, 10);
         Application.Refresh ();
 
         Assert.True (textView.WordWrap);
@@ -1229,7 +1229,7 @@ This is a test             ",
 
         super.Add (sbv);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (width, height);
+        ((FakeDriver)Application.Driver!).SetBufferSize (width, height);
 
         var expected = @"
 ┌─┐
diff --git a/UnitTests/Views/ScrollViewTests.cs b/UnitTests/Views/ScrollViewTests.cs
index ceab4e63a..c4d14c235 100644
--- a/UnitTests/Views/ScrollViewTests.cs
+++ b/UnitTests/Views/ScrollViewTests.cs
@@ -362,7 +362,7 @@ public class ScrollViewTests (ITestOutputHelper output)
     [SetupFakeDriver]
     public void ContentBottomRightCorner_Draw ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize (30, 30);
+        ((FakeDriver)Application.Driver!).SetBufferSize (30, 30);
 
         var top = new View { Width = 30, Height = 30, ColorScheme = new() { Normal = Attribute.Default } };
 
diff --git a/UnitTests/Views/TableViewTests.cs b/UnitTests/Views/TableViewTests.cs
index 515e3f8bd..6740120f6 100644
--- a/UnitTests/Views/TableViewTests.cs
+++ b/UnitTests/Views/TableViewTests.cs
@@ -2196,7 +2196,7 @@ public class TableViewTests (ITestOutputHelper output)
     [SetupFakeDriver]
     public void TestEnumerableDataSource_BasicTypes ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize(100,100);
+        ((FakeDriver)Application.Driver!).SetBufferSize(100,100);
         var tv = new TableView ();
         tv.ColorScheme = Colors.ColorSchemes ["TopLevel"];
         tv.Viewport = new (0, 0, 50, 6);
diff --git a/UnitTests/Views/TextFieldTests.cs b/UnitTests/Views/TextFieldTests.cs
index e50617933..ed3a35775 100644
--- a/UnitTests/Views/TextFieldTests.cs
+++ b/UnitTests/Views/TextFieldTests.cs
@@ -67,7 +67,7 @@ public class TextFieldTests (ITestOutputHelper output)
 
             for (var i = 0; i < 16; i++)
             {
-                item += Application.Driver.Contents [0, i].Rune;
+                item += Application.Driver?.Contents [0, i].Rune;
             }
 
             return item;
@@ -164,7 +164,7 @@ public class TextFieldTests (ITestOutputHelper output)
 
         // Caption has no effect when focused
         tf.Caption = caption;
-        Application.Driver.SendKeys ('\t', ConsoleKey.Tab, false, false, false);
+        Application.Driver?.SendKeys ('\t', ConsoleKey.Tab, false, false, false);
         Assert.False (tf.HasFocus);
 
         tf.Draw ();
@@ -184,7 +184,7 @@ public class TextFieldTests (ITestOutputHelper output)
         TextField tf = GetTextFieldsInView ();
 
         tf.Caption = caption;
-        Application.Driver.SendKeys ('\t', ConsoleKey.Tab, false, false, false);
+        Application.Driver?.SendKeys ('\t', ConsoleKey.Tab, false, false, false);
         Assert.False (tf.HasFocus);
 
         tf.Draw ();
@@ -205,7 +205,7 @@ public class TextFieldTests (ITestOutputHelper output)
         TestHelpers.AssertDriverContentsAre ("", output);
 
         tf.Caption = "Enter txt";
-        Application.Driver.SendKeys ('\t', ConsoleKey.Tab, false, false, false);
+        Application.Driver?.SendKeys ('\t', ConsoleKey.Tab, false, false, false);
 
         // Caption should appear when not focused and no text
         Assert.False (tf.HasFocus);
@@ -234,7 +234,7 @@ public class TextFieldTests (ITestOutputHelper output)
         tf.Draw ();
         TestHelpers.AssertDriverContentsAre ("", output);
 
-        Application.Driver.SendKeys ('\t', ConsoleKey.Tab, false, false, false);
+        Application.Driver?.SendKeys ('\t', ConsoleKey.Tab, false, false, false);
 
         Assert.False (tf.HasFocus);
         tf.Draw ();
@@ -347,7 +347,7 @@ public class TextFieldTests (ITestOutputHelper output)
 
         Assert.Equal (
                       "TextField with some more test text. Unicode shouldn't 𝔹Aℝ𝔽!",
-                      Application.Driver.Clipboard.GetClipboardData ()
+                      Application.Driver?.Clipboard.GetClipboardData ()
                      );
         Assert.Equal (string.Empty, _textField.Text);
         _textField.Paste ();
@@ -374,7 +374,7 @@ public class TextFieldTests (ITestOutputHelper output)
         Assert.Equal (32, _textField.CursorPosition);
         _textField.SelectAll ();
         _textField.Cut ();
-        Assert.Equal ("TAB to jump between text fields.", Application.Driver.Clipboard.GetClipboardData ());
+        Assert.Equal ("TAB to jump between text fields.", Application.Driver?.Clipboard.GetClipboardData ());
         Assert.Equal (string.Empty, _textField.Text);
         Assert.Equal (0, _textField.CursorPosition);
         _textField.Paste ();
diff --git a/UnitTests/Views/TextViewTests.cs b/UnitTests/Views/TextViewTests.cs
index f260dd162..f9ff520dd 100644
--- a/UnitTests/Views/TextViewTests.cs
+++ b/UnitTests/Views/TextViewTests.cs
@@ -609,7 +609,7 @@ public class TextViewTests
 
         Assert.Equal (
                       "TextView with some more test text. Unicode shouldn't 𝔹Aℝ𝔽!",
-                      Application.Driver.Clipboard.GetClipboardData ()
+                      Application.Driver?.Clipboard.GetClipboardData ()
                      );
         Assert.Equal (string.Empty, _textView.Text);
         _textView.Paste ();
@@ -1018,7 +1018,7 @@ This is the second line.
             tv.NewMouseEvent (new MouseEvent { Flags = MouseFlags.WheeledRight });
             Assert.Equal (Math.Min (i + 1, 11), tv.LeftColumn);
             Application.PositionCursor (top);
-            Application.Driver.GetCursorVisibility (out CursorVisibility cursorVisibility);
+            Application.Driver!.GetCursorVisibility (out CursorVisibility cursorVisibility);
             Assert.Equal (CursorVisibility.Invisible, cursorVisibility);
         }
 
@@ -1028,7 +1028,7 @@ This is the second line.
             Assert.Equal (i - 1, tv.LeftColumn);
 
             Application.PositionCursor (top);
-            Application.Driver.GetCursorVisibility (out CursorVisibility cursorVisibility);
+            Application.Driver!.GetCursorVisibility (out CursorVisibility cursorVisibility);
 
             if (i - 1 == 0)
             {
@@ -1070,7 +1070,7 @@ This is the second line.
             tv.NewMouseEvent (new MouseEvent { Flags = MouseFlags.WheeledDown });
             Application.PositionCursor (top);
             Assert.Equal (i + 1, tv.TopRow);
-            Application.Driver.GetCursorVisibility (out CursorVisibility cursorVisibility);
+            Application.Driver!.GetCursorVisibility (out CursorVisibility cursorVisibility);
             Assert.Equal (CursorVisibility.Invisible, cursorVisibility);
         }
 
@@ -1081,7 +1081,7 @@ This is the second line.
             Assert.Equal (i - 1, tv.TopRow);
 
             Application.PositionCursor (top);
-            Application.Driver.GetCursorVisibility (out CursorVisibility cursorVisibility);
+            Application.Driver!.GetCursorVisibility (out CursorVisibility cursorVisibility);
 
             if (i - 1 == 0)
             {
@@ -6697,7 +6697,7 @@ TAB to jump between text field",
         var top = new Toplevel ();
         top.Add (win);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (15, 15);
+        ((FakeDriver)Application.Driver!).SetBufferSize (15, 15);
         Application.Refresh ();
 
         //this passes
@@ -6774,7 +6774,7 @@ TAB to jump between text field",
         var top = new Toplevel ();
         top.Add (win);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (15, 15);
+        ((FakeDriver)Application.Driver!).SetBufferSize (15, 15);
         Application.Refresh ();
 
         //this passes
@@ -6899,8 +6899,8 @@ This is the second line.
                                                       _output
                                                      );
 
-        ((FakeDriver)Application.Driver).SetBufferSize (6, 25);
-        tv.SetRelativeLayout (Application.Driver.Screen.Size);
+        ((FakeDriver)Application.Driver!).SetBufferSize (6, 25);
+        tv.SetRelativeLayout (Application.Driver!.Screen.Size);
         tv.Draw ();
         Assert.Equal (new Point (4, 2), tv.CursorPosition);
         Assert.Equal (new Point (12, 0), cp);
diff --git a/UnitTests/Views/ToplevelTests.cs b/UnitTests/Views/ToplevelTests.cs
index abbfdeb59..c19c72bb1 100644
--- a/UnitTests/Views/ToplevelTests.cs
+++ b/UnitTests/Views/ToplevelTests.cs
@@ -44,8 +44,8 @@ public partial class ToplevelTests (ITestOutputHelper output)
                                              Assert.Equal ("Top1", Application.Top.Text);
                                              Assert.Equal (0, Application.Top.Frame.X);
                                              Assert.Equal (0, Application.Top.Frame.Y);
-                                             Assert.Equal (Application.Driver.Cols, Application.Top.Frame.Width);
-                                             Assert.Equal (Application.Driver.Rows, Application.Top.Frame.Height);
+                                             Assert.Equal (Application.Driver!.Cols, Application.Top.Frame.Width);
+                                             Assert.Equal (Application.Driver!.Rows, Application.Top.Frame.Height);
 
                                              Application.OnKeyPressed (new (Key.CtrlMask | Key.R));
 
@@ -54,8 +54,8 @@ public partial class ToplevelTests (ITestOutputHelper output)
                                              Assert.Equal ("Top2", Application.Top.Text);
                                              Assert.Equal (0, Application.Top.Frame.X);
                                              Assert.Equal (0, Application.Top.Frame.Y);
-                                             Assert.Equal (Application.Driver.Cols, Application.Top.Frame.Width);
-                                             Assert.Equal (Application.Driver.Rows, Application.Top.Frame.Height);
+                                             Assert.Equal (Application.Driver!.Cols, Application.Top.Frame.Width);
+                                             Assert.Equal (Application.Driver!.Rows, Application.Top.Frame.Height);
 
                                              Application.OnKeyPressed (new (Key.CtrlMask | Key.C));
 
@@ -64,8 +64,8 @@ public partial class ToplevelTests (ITestOutputHelper output)
                                              Assert.Equal ("Top1", Application.Top.Text);
                                              Assert.Equal (0, Application.Top.Frame.X);
                                              Assert.Equal (0, Application.Top.Frame.Y);
-                                             Assert.Equal (Application.Driver.Cols, Application.Top.Frame.Width);
-                                             Assert.Equal (Application.Driver.Rows, Application.Top.Frame.Height);
+                                             Assert.Equal (Application.Driver!.Cols, Application.Top.Frame.Width);
+                                             Assert.Equal (Application.Driver!.Rows, Application.Top.Frame.Height);
 
                                              Application.OnKeyPressed (new (Key.CtrlMask | Key.R));
 
@@ -74,8 +74,8 @@ public partial class ToplevelTests (ITestOutputHelper output)
                                              Assert.Equal ("Top2", Application.Top.Text);
                                              Assert.Equal (0, Application.Top.Frame.X);
                                              Assert.Equal (0, Application.Top.Frame.Y);
-                                             Assert.Equal (Application.Driver.Cols, Application.Top.Frame.Width);
-                                             Assert.Equal (Application.Driver.Rows, Application.Top.Frame.Height);
+                                             Assert.Equal (Application.Driver!.Cols, Application.Top.Frame.Width);
+                                             Assert.Equal (Application.Driver!.Rows, Application.Top.Frame.Height);
 
                                              Application.OnKeyPressed (new (Key.CtrlMask | Key.C));
 
@@ -84,8 +84,8 @@ public partial class ToplevelTests (ITestOutputHelper output)
                                              Assert.Equal ("Top1", Application.Top.Text);
                                              Assert.Equal (0, Application.Top.Frame.X);
                                              Assert.Equal (0, Application.Top.Frame.Y);
-                                             Assert.Equal (Application.Driver.Cols, Application.Top.Frame.Width);
-                                             Assert.Equal (Application.Driver.Rows, Application.Top.Frame.Height);
+                                             Assert.Equal (Application.Driver!.Cols, Application.Top.Frame.Width);
+                                             Assert.Equal (Application.Driver!.Rows, Application.Top.Frame.Height);
 
                                              Application.OnKeyPressed (new (Key.CtrlMask | Key.Q));
 
@@ -675,7 +675,7 @@ public partial class ToplevelTests (ITestOutputHelper output)
 
                                      if (iterations == 0)
                                      {
-                                         ((FakeDriver)Application.Driver).SetBufferSize (15, 7);
+                                         ((FakeDriver)Application.Driver!).SetBufferSize (15, 7);
 
                                          // Don't use MessageBox here; it's too complicated for this unit test; just use Window
                                          testWindow = new ()
@@ -794,7 +794,7 @@ public partial class ToplevelTests (ITestOutputHelper output)
 
                                      if (iterations == 0)
                                      {
-                                         ((FakeDriver)Application.Driver).SetBufferSize (30, 10);
+                                         ((FakeDriver)Application.Driver!).SetBufferSize (30, 10);
                                      }
                                      else if (iterations == 1)
                                      {
@@ -896,10 +896,10 @@ public partial class ToplevelTests (ITestOutputHelper output)
         top.BeginInit ();
         top.EndInit ();
 
-        Exception exception = Record.Exception (() => ((FakeDriver)Application.Driver).SetBufferSize (0, 10));
+        Exception exception = Record.Exception (() => ((FakeDriver)Application.Driver!).SetBufferSize (0, 10));
         Assert.Null (exception);
 
-        exception = Record.Exception (() => ((FakeDriver)Application.Driver).SetBufferSize (10, 0));
+        exception = Record.Exception (() => ((FakeDriver)Application.Driver!).SetBufferSize (10, 0));
         Assert.Null (exception);
     }
 
@@ -1085,13 +1085,13 @@ public partial class ToplevelTests (ITestOutputHelper output)
 
         Assert.True (tf.HasFocus);
         Application.PositionCursor (top);
-        Application.Driver.GetCursorVisibility (out CursorVisibility cursor);
+        Application.Driver!.GetCursorVisibility (out CursorVisibility cursor);
         Assert.Equal (CursorVisibility.Default, cursor);
 
         view.Enabled = false;
         Assert.False (tf.HasFocus);
         Application.PositionCursor (top);
-        Application.Driver.GetCursorVisibility (out cursor);
+        Application.Driver!.GetCursorVisibility (out cursor);
         Assert.Equal (CursorVisibility.Invisible, cursor);
         top.Dispose ();
     }
@@ -1209,7 +1209,7 @@ public partial class ToplevelTests (ITestOutputHelper output)
         Toplevel top = new ();
         var window = new Window { Width = 20, Height = 3, Arrangement = ViewArrangement.Movable };
         RunState rsTop = Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (40, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (40, 10);
         RunState rsWindow = Application.Begin (window);
         Application.Refresh ();
         Assert.Equal (new (0, 0, 40, 10), top.Frame);
@@ -1232,7 +1232,7 @@ public partial class ToplevelTests (ITestOutputHelper output)
         Assert.Equal (new (0, 0, 20, 3), window.Frame);
 
         // Changes Top size to same size as Dialog more menu and scroll bar
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 3);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 3);
 
         Application.OnMouseEvent (
                                   new ()
@@ -1245,7 +1245,7 @@ public partial class ToplevelTests (ITestOutputHelper output)
         Assert.Equal (new (0, 0, 20, 3), window.Frame);
 
         // Changes Top size smaller than Dialog size
-        ((FakeDriver)Application.Driver).SetBufferSize (19, 2);
+        ((FakeDriver)Application.Driver!).SetBufferSize (19, 2);
 
         Application.OnMouseEvent (
                                   new ()
@@ -1338,7 +1338,7 @@ public partial class ToplevelTests (ITestOutputHelper output)
     {
         Toplevel top = new ();
         RunState rsTop = Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 20);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 20);
 
         var testWindow = new Window { X = 2, Y = 1, Width = 15, Height = 10 };
         Assert.Equal (new (2, 1, 15, 10), testWindow.Frame);
@@ -1360,7 +1360,7 @@ public partial class ToplevelTests (ITestOutputHelper output)
         var win = new Window ();
         top.Add (win);
         RunState rsTop = Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 20);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 20);
 
         Assert.Equal (new (0, 0, 20, 20), win.Frame);
 
@@ -1389,8 +1389,8 @@ public partial class ToplevelTests (ITestOutputHelper output)
                                {
                                    Assert.Equal (new (1, 3, 18, 16), viewAddedToTop.Frame);
 
-                                   Rectangle savedClip = Application.Driver.Clip;
-                                   Application.Driver.Clip = top.Frame;
+                                   Rectangle savedClip = Application.Driver!.Clip;
+                                   Application.Driver!.Clip = top.Frame;
                                    viewAddedToTop.Draw ();
                                    top.Move (2, 15);
                                    View.Driver.AddStr ("One");
@@ -1398,7 +1398,7 @@ public partial class ToplevelTests (ITestOutputHelper output)
                                    View.Driver.AddStr ("Two");
                                    top.Move (2, 17);
                                    View.Driver.AddStr ("Three");
-                                   Application.Driver.Clip = savedClip;
+                                   Application.Driver!.Clip = savedClip;
 
                                    Application.Current.DrawContentComplete -= OnDrawContentComplete;
                                }
diff --git a/UnitTests/Views/TreeTableSourceTests.cs b/UnitTests/Views/TreeTableSourceTests.cs
index 0b54be84d..39e18327b 100644
--- a/UnitTests/Views/TreeTableSourceTests.cs
+++ b/UnitTests/Views/TreeTableSourceTests.cs
@@ -29,7 +29,7 @@ public class TreeTableSourceTests : IDisposable
     [SetupFakeDriver]
     public void TestTreeTableSource_BasicExpanding_WithKeyboard ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize (100, 100);
+        ((FakeDriver)Application.Driver!).SetBufferSize (100, 100);
         TableView tv = GetTreeTable (out _);
 
         tv.Style.GetOrCreateColumnStyle (1).MinAcceptableWidth = 1;
@@ -88,7 +88,7 @@ public class TreeTableSourceTests : IDisposable
     [SetupFakeDriver]
     public void TestTreeTableSource_BasicExpanding_WithMouse ()
     {
-        ((FakeDriver)Application.Driver).SetBufferSize (100, 100);
+        ((FakeDriver)Application.Driver!).SetBufferSize (100, 100);
 
         TableView tv = GetTreeTable (out _);
 
diff --git a/UnitTests/Views/TreeViewTests.cs b/UnitTests/Views/TreeViewTests.cs
index 11d85acdb..a770d1d9d 100644
--- a/UnitTests/Views/TreeViewTests.cs
+++ b/UnitTests/Views/TreeViewTests.cs
@@ -114,7 +114,7 @@ public class TreeViewTests
         tv.SelectAll ();
         tv.CursorVisibility = CursorVisibility.Default;
         Application.PositionCursor (top);
-        Application.Driver.GetCursorVisibility (out CursorVisibility visibility);
+        Application.Driver!.GetCursorVisibility (out CursorVisibility visibility);
         Assert.Equal (CursorVisibility.Default, tv.CursorVisibility);
         Assert.Equal (CursorVisibility.Default, visibility);
         top.Dispose ();
diff --git a/UnitTests/Views/WindowTests.cs b/UnitTests/Views/WindowTests.cs
index 24ea77876..6df5361e3 100644
--- a/UnitTests/Views/WindowTests.cs
+++ b/UnitTests/Views/WindowTests.cs
@@ -53,7 +53,7 @@ public class WindowTests
         Toplevel top = new ();
         top.Add (win);
         Application.Begin (top);
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 10);
 
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       @"
@@ -70,7 +70,7 @@ public class WindowTests
                                                       _output
                                                      );
 
-        ((FakeDriver)Application.Driver).SetBufferSize (40, 20);
+        ((FakeDriver)Application.Driver!).SetBufferSize (40, 20);
 
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       @"
@@ -97,7 +97,7 @@ public class WindowTests
                                                       _output
                                                      );
 
-        ((FakeDriver)Application.Driver).SetBufferSize (20, 10);
+        ((FakeDriver)Application.Driver!).SetBufferSize (20, 10);
 
         TestHelpers.AssertDriverContentsWithFrameAre (
                                                       @"

From 2e0a9a7c688f822adec71c98a6205a17d5c65f6f Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Mon, 22 Jul 2024 16:59:10 -0600
Subject: [PATCH 03/33] Fixed nullable warnings

---
 Terminal.Gui/Application/Application.Mouse.cs |  2 +-
 Terminal.Gui/Application/Application.cs       |  4 ++--
 Terminal.Gui/View/Layout/ViewLayout.cs        |  6 +++---
 Terminal.sln.DotSettings                      |  3 ++-
 UICatalog/UICatalog.cs                        | 10 +++++-----
 UnitTests/ConsoleDrivers/ClipRegionTests.cs   |  4 ++--
 6 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/Terminal.Gui/Application/Application.Mouse.cs b/Terminal.Gui/Application/Application.Mouse.cs
index 4d3fb6129..7cad055d5 100644
--- a/Terminal.Gui/Application/Application.Mouse.cs
+++ b/Terminal.Gui/Application/Application.Mouse.cs
@@ -195,7 +195,7 @@ public static partial class Application // Mouse handling
             {
                 // This occurs when there are multiple overlapped "tops"
                 // E.g. "Mdi" - in the Background Worker Scenario
-                View? top = FindDeepestTop (Top, mouseEvent.Position);
+                View? top = FindDeepestTop (Top!, mouseEvent.Position);
                 view = View.FindDeepestView (top, mouseEvent.Position);
 
                 if (view is { } && view != OverlappedTop && top != Current && top is { })
diff --git a/Terminal.Gui/Application/Application.cs b/Terminal.Gui/Application/Application.cs
index 1561413e9..c8aa2536a 100644
--- a/Terminal.Gui/Application/Application.cs
+++ b/Terminal.Gui/Application/Application.cs
@@ -19,7 +19,7 @@ namespace Terminal.Gui;
 public static partial class Application
 {
     /// <summary>Gets all cultures supported by the application without the invariant language.</summary>
-    public static List<CultureInfo> SupportedCultures { get; private set; }
+    public static List<CultureInfo>? SupportedCultures { get; private set; }
 
     internal static List<CultureInfo> GetSupportedCultures ()
     {
@@ -257,7 +257,7 @@ public static partial class Application
 
             foreach (Toplevel? t in savedToplevels)
             {
-                if (!t.Modal && t != Current && t != top && t != savedToplevels [index])
+                if (!t!.Modal && t != Current && t != top && t != savedToplevels [index])
                 {
                     lock (_topLevels)
                     {
diff --git a/Terminal.Gui/View/Layout/ViewLayout.cs b/Terminal.Gui/View/Layout/ViewLayout.cs
index 637d1f0ca..4e2531745 100644
--- a/Terminal.Gui/View/Layout/ViewLayout.cs
+++ b/Terminal.Gui/View/Layout/ViewLayout.cs
@@ -344,7 +344,7 @@ public partial class View
             if (found is { })
             {
                 start = found;
-                viewportOffset = found.Parent.Frame.Location;
+                viewportOffset = found.Parent?.Frame.Location ?? Point.Empty;
             }
 
             int startOffsetX = currentLocation.X - (start.Frame.X + viewportOffset.X);
@@ -796,7 +796,7 @@ public partial class View
                 //}
                 if (dv.Target != this)
                 {
-                    nEdges.Add ((dv.Target, from));
+                    nEdges.Add ((dv.Target!, from));
                 }
 
                 return;
@@ -819,7 +819,7 @@ public partial class View
                 //}
                 if (pv.Target != this)
                 {
-                    nEdges.Add ((pv.Target, from));
+                    nEdges.Add ((pv.Target!, from));
                 }
 
                 return;
diff --git a/Terminal.sln.DotSettings b/Terminal.sln.DotSettings
index e83ed7026..bf87e5ea9 100644
--- a/Terminal.sln.DotSettings
+++ b/Terminal.sln.DotSettings
@@ -1,4 +1,4 @@
-<wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
+<wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
 	<s:String x:Key="/Default/CodeEditing/GenerateMemberBody/AccessorImplementationKind/@EntryValue">BackingField</s:String>
 	<s:String x:Key="/Default/CodeEditing/GenerateMemberBody/DocumentationGenerationKind/@EntryValue">Inherit</s:String>
 	<s:Boolean x:Key="/Default/CodeEditing/GenerateMemberBody/PlaceBackingFieldAboveProperty/@EntryValue">True</s:Boolean>
@@ -390,6 +390,7 @@
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/UserRules/=53eecf85_002Dd821_002D40e8_002Dac97_002Dfdb734542b84/@EntryIndexedValue">&lt;Policy&gt;&lt;Descriptor Staticness="Instance" AccessRightKinds="Protected, ProtectedInternal, Internal, Public, PrivateProtected" Description="Instance fields (not private)"&gt;&lt;ElementKinds&gt;&lt;Kind Name="FIELD" /&gt;&lt;Kind Name="READONLY_FIELD" /&gt;&lt;/ElementKinds&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" Prefix="_" Suffix="" Style="aaBb" /&gt;&lt;/Policy&gt;</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/UserRules/=70345118_002D4b40_002D4ece_002D937c_002Dbbeb7a0b2e70/@EntryIndexedValue">&lt;Policy&gt;&lt;Descriptor Staticness="Static" AccessRightKinds="Protected, ProtectedInternal, Internal, Public, PrivateProtected" Description="Static fields (not private)"&gt;&lt;ElementKinds&gt;&lt;Kind Name="FIELD" /&gt;&lt;/ElementKinds&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" Prefix="_" Suffix="" Style="aaBb" /&gt;&lt;/Policy&gt;</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/UserRules/=a0b4bc4d_002Dd13b_002D4a37_002Db37e_002Dc9c6864e4302/@EntryIndexedValue">&lt;Policy&gt;&lt;Descriptor Staticness="Any" AccessRightKinds="Any" Description="Types and namespaces"&gt;&lt;ElementKinds&gt;&lt;Kind Name="NAMESPACE" /&gt;&lt;Kind Name="CLASS" /&gt;&lt;Kind Name="STRUCT" /&gt;&lt;Kind Name="ENUM" /&gt;&lt;Kind Name="DELEGATE" /&gt;&lt;/ElementKinds&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" Prefix="" Suffix="" Style="AaBb"&gt;&lt;ExtraRule Prefix="" Suffix="" Style="AaBb_AaBb" /&gt;&lt;/Policy&gt;&lt;/Policy&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/UserRules/=a4f433b8_002Dabcd_002D4e55_002Da08f_002D82e78cef0f0c/@EntryIndexedValue">&lt;Policy&gt;&lt;Descriptor Staticness="Any" AccessRightKinds="Any" Description="Local constants"&gt;&lt;ElementKinds&gt;&lt;Kind Name="LOCAL_CONSTANT" /&gt;&lt;/ElementKinds&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" Prefix="" Suffix="" Style="AA_BB" /&gt;&lt;/Policy&gt;</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/UserRules/=c873eafb_002Dd57f_002D481d_002D8c93_002D77f6863c2f88/@EntryIndexedValue">&lt;Policy&gt;&lt;Descriptor Staticness="Static" AccessRightKinds="Protected, ProtectedInternal, Internal, Public, PrivateProtected" Description="Static readonly fields (not private)"&gt;&lt;ElementKinds&gt;&lt;Kind Name="READONLY_FIELD" /&gt;&lt;/ElementKinds&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" Prefix="_" Suffix="" Style="aaBb" /&gt;&lt;/Policy&gt;</s:String>
 	<s:Boolean x:Key="/Default/Environment/InjectedLayers/FileInjectedLayer/=A92AB40A0394A342A0BE0D83FEEA5DBF/@KeyIndexDefined">True</s:Boolean>
 	<s:String x:Key="/Default/Environment/InjectedLayers/FileInjectedLayer/=A92AB40A0394A342A0BE0D83FEEA5DBF/RelativePath/@EntryValue">..\Terminal.sln.ToDo.DotSettings</s:String>
diff --git a/UICatalog/UICatalog.cs b/UICatalog/UICatalog.cs
index dd4184cb4..f9ac4a503 100644
--- a/UICatalog/UICatalog.cs
+++ b/UICatalog/UICatalog.cs
@@ -666,7 +666,7 @@ internal class UICatalogApp
 
             MiIsMouseDisabled!.Checked = Application.IsMouseDisabled;
 
-            Application.Top.SetNeedsDisplay ();
+            Application.Top!.SetNeedsDisplay ();
         }
 
         public MenuItem []? CreateThemeMenuItems ()
@@ -835,7 +835,7 @@ internal class UICatalogApp
                                    }
 
                                    Diagnostics = _diagnosticFlags;
-                                   Application.Top.SetNeedsDisplay ();
+                                   Application.Top!.SetNeedsDisplay ();
                                };
                 menuItems.Add (item);
             }
@@ -1061,7 +1061,7 @@ internal class UICatalogApp
                                                 ShowStatusBar = StatusBar.Visible;
 
                                                 int height = StatusBar.Visible ? 1 : 0;
-                                                CategoryList.Height = Dim.Fill (height);
+                                                CategoryList!.Height = Dim.Fill (height);
                                                 ScenarioList.Height = Dim.Fill (height);
 
                                                 // ContentPane.Height = Dim.Fill (height);
@@ -1071,7 +1071,7 @@ internal class UICatalogApp
             }
 
             Loaded -= LoadedHandler;
-            CategoryList.EnsureSelectedItemVisible ();
+            CategoryList!.EnsureSelectedItemVisible ();
             ScenarioList.EnsureSelectedCellIsVisible ();
         }
 
@@ -1082,7 +1082,7 @@ internal class UICatalogApp
             if (_selectedScenario is null)
             {
                 // Save selected item state
-                _cachedCategoryIndex = CategoryList.SelectedItem;
+                _cachedCategoryIndex = CategoryList!.SelectedItem;
                 _cachedScenarioIndex = ScenarioList.SelectedRow;
 
                 // Create new instance of scenario (even though Scenarios contains instances)
diff --git a/UnitTests/ConsoleDrivers/ClipRegionTests.cs b/UnitTests/ConsoleDrivers/ClipRegionTests.cs
index 8a90f2e4d..73eff741d 100644
--- a/UnitTests/ConsoleDrivers/ClipRegionTests.cs
+++ b/UnitTests/ConsoleDrivers/ClipRegionTests.cs
@@ -7,12 +7,12 @@ namespace Terminal.Gui.DriverTests;
 
 public class ClipRegionTests
 {
-    private readonly ITestOutputHelper output;
+    private readonly ITestOutputHelper _output;
 
     public ClipRegionTests (ITestOutputHelper output)
     {
         ConsoleDriver.RunningUnitTests = true;
-        this.output = output;
+        this._output = output;
     }
 
     [Theory]

From 0b8e4342d4aff89afbe09f872e510e19892ea189 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Mon, 22 Jul 2024 17:05:06 -0600
Subject: [PATCH 04/33] Applicaation Toplevel handling moved to separate file

---
 Terminal.Gui/Application/Application.Run.cs   |   5 +
 .../Application/Application.Toplevel.cs       | 214 ++++++++++++++++++
 Terminal.Gui/Application/Application.cs       |   7 +-
 3 files changed, 224 insertions(+), 2 deletions(-)
 create mode 100644 Terminal.Gui/Application/Application.Toplevel.cs

diff --git a/Terminal.Gui/Application/Application.Run.cs b/Terminal.Gui/Application/Application.Run.cs
index 34189d9fc..06c191230 100644
--- a/Terminal.Gui/Application/Application.Run.cs
+++ b/Terminal.Gui/Application/Application.Run.cs
@@ -5,6 +5,8 @@ namespace Terminal.Gui;
 
 public static partial class Application // Run (Begin, Run, End, Stop)
 {
+    // When `End ()` is called, it is possible `RunState.Toplevel` is a different object than `Top`.
+    // This variable is set in `End` in this case so that `Begin` correctly sets `Top`.
     private static Toplevel _cachedRunStateToplevel;
 
     /// <summary>
@@ -485,6 +487,9 @@ public static partial class Application // Run (Begin, Run, End, Stop)
                           );
     }
 
+    // TODO: Determine if this is really needed. The only code that calls WakeUp I can find
+    // is ProgressBarStyles, and it's not clear it needs to.
+
     /// <summary>Wakes up the running application that might be waiting on input.</summary>
     public static void Wakeup () { MainLoop?.Wakeup (); }
 
diff --git a/Terminal.Gui/Application/Application.Toplevel.cs b/Terminal.Gui/Application/Application.Toplevel.cs
new file mode 100644
index 000000000..6d25f7d02
--- /dev/null
+++ b/Terminal.Gui/Application/Application.Toplevel.cs
@@ -0,0 +1,214 @@
+namespace Terminal.Gui;
+
+public static partial class Application // Toplevel handling
+{
+    /// <summary>Holds the stack of TopLevel views.</summary>
+
+    // BUGBUG: Technically, this is not the full lst of TopLevels. There be dragons here, e.g. see how Toplevel.Id is used. What
+    // about TopLevels that are just a SubView of another View?
+    internal static readonly Stack<Toplevel> _topLevels = new ();
+
+    /// <summary>The <see cref="Toplevel"/> object used for the application on startup (<seealso cref="Top"/>)</summary>
+    /// <value>The top.</value>
+    public static Toplevel Top { get; private set; }
+
+    /// <summary>
+    ///     The current <see cref="Toplevel"/> object. This is updated in <see cref="Application.Begin"/> enters and leaves to
+    ///     point to the current
+    ///     <see cref="Toplevel"/> .
+    /// </summary>
+    /// <remarks>
+    ///     Only relevant in scenarios where <see cref="Toplevel.IsOverlappedContainer"/> is <see langword="true"/>.
+    /// </remarks>
+    /// <value>The current.</value>
+    public static Toplevel Current { get; private set; }
+
+    private static void EnsureModalOrVisibleAlwaysOnTop (Toplevel topLevel)
+    {
+        if (!topLevel.Running
+            || (topLevel == Current && topLevel.Visible)
+            || OverlappedTop == null
+            || _topLevels.Peek ().Modal)
+        {
+            return;
+        }
+
+        foreach (Toplevel top in _topLevels.Reverse ())
+        {
+            if (top.Modal && top != Current)
+            {
+                MoveCurrent (top);
+
+                return;
+            }
+        }
+
+        if (!topLevel.Visible && topLevel == Current)
+        {
+            OverlappedMoveNext ();
+        }
+    }
+
+    private static Toplevel FindDeepestTop (Toplevel start, in Point location)
+    {
+        if (!start.Frame.Contains (location))
+        {
+            return null;
+        }
+
+        if (_topLevels is { Count: > 0 })
+        {
+            int rx = location.X - start.Frame.X;
+            int ry = location.Y - start.Frame.Y;
+
+            foreach (Toplevel t in _topLevels)
+            {
+                if (t != Current)
+                {
+                    if (t != start && t.Visible && t.Frame.Contains (rx, ry))
+                    {
+                        start = t;
+
+                        break;
+                    }
+                }
+            }
+        }
+
+        return start;
+    }
+
+    private static View FindTopFromView (View view)
+    {
+        View top = view?.SuperView is { } && view?.SuperView != Top
+                       ? view.SuperView
+                       : view;
+
+        while (top?.SuperView is { } && top?.SuperView != Top)
+        {
+            top = top.SuperView;
+        }
+
+        return top;
+    }
+
+    private static bool MoveCurrent (Toplevel top)
+    {
+        // The Current is modal and the top is not modal Toplevel then
+        // the Current must be moved above the first not modal Toplevel.
+        if (OverlappedTop is { }
+            && top != OverlappedTop
+            && top != Current
+            && Current?.Modal == true
+            && !_topLevels.Peek ().Modal)
+        {
+            lock (_topLevels)
+            {
+                _topLevels.MoveTo (Current, 0, new ToplevelEqualityComparer ());
+            }
+
+            var index = 0;
+            Toplevel [] savedToplevels = _topLevels.ToArray ();
+
+            foreach (Toplevel t in savedToplevels)
+            {
+                if (!t!.Modal && t != Current && t != top && t != savedToplevels [index])
+                {
+                    lock (_topLevels)
+                    {
+                        _topLevels.MoveTo (top, index, new ToplevelEqualityComparer ());
+                    }
+                }
+
+                index++;
+            }
+
+            return false;
+        }
+
+        // The Current and the top are both not running Toplevel then
+        // the top must be moved above the first not running Toplevel.
+        if (OverlappedTop is { }
+            && top != OverlappedTop
+            && top != Current
+            && Current?.Running == false
+            && top?.Running == false)
+        {
+            lock (_topLevels)
+            {
+                _topLevels.MoveTo (Current, 0, new ToplevelEqualityComparer ());
+            }
+
+            var index = 0;
+
+            foreach (Toplevel t in _topLevels.ToArray ())
+            {
+                if (!t.Running && t != Current && index > 0)
+                {
+                    lock (_topLevels)
+                    {
+                        _topLevels.MoveTo (top, index - 1, new ToplevelEqualityComparer ());
+                    }
+                }
+
+                index++;
+            }
+
+            return false;
+        }
+
+        if ((OverlappedTop is { } && top?.Modal == true && _topLevels.Peek () != top)
+            || (OverlappedTop is { } && Current != OverlappedTop && Current?.Modal == false && top == OverlappedTop)
+            || (OverlappedTop is { } && Current?.Modal == false && top != Current)
+            || (OverlappedTop is { } && Current?.Modal == true && top == OverlappedTop))
+        {
+            lock (_topLevels)
+            {
+                _topLevels.MoveTo (top, 0, new ToplevelEqualityComparer ());
+                Current = top;
+            }
+        }
+
+        return true;
+    }
+
+    /// <summary>Invoked when the terminal's size changed. The new size of the terminal is provided.</summary>
+    /// <remarks>
+    ///     Event handlers can set <see cref="SizeChangedEventArgs.Cancel"/> to <see langword="true"/> to prevent
+    ///     <see cref="Application"/> from changing it's size to match the new terminal size.
+    /// </remarks>
+    public static event EventHandler<SizeChangedEventArgs> SizeChanging;
+
+    /// <summary>
+    ///     Called when the application's size changes. Sets the size of all <see cref="Toplevel"/>s and fires the
+    ///     <see cref="SizeChanging"/> event.
+    /// </summary>
+    /// <param name="args">The new size.</param>
+    /// <returns><see lanword="true"/>if the size was changed.</returns>
+    public static bool OnSizeChanging (SizeChangedEventArgs args)
+    {
+        SizeChanging?.Invoke (null, args);
+
+        if (args.Cancel || args.Size is null)
+        {
+            return false;
+        }
+
+        foreach (Toplevel t in _topLevels)
+        {
+            t.SetRelativeLayout (args.Size.Value);
+            t.LayoutSubviews ();
+            t.PositionToplevels ();
+            t.OnSizeChanging (new (args.Size));
+
+            if (PositionCursor (t))
+            {
+                Driver.UpdateCursor ();
+            }
+        }
+
+        Refresh ();
+
+        return true;
+    }
+}
diff --git a/Terminal.Gui/Application/Application.cs b/Terminal.Gui/Application/Application.cs
index c8aa2536a..202b66044 100644
--- a/Terminal.Gui/Application/Application.cs
+++ b/Terminal.Gui/Application/Application.cs
@@ -9,13 +9,16 @@ namespace Terminal.Gui;
 /// <example>
 ///     <code>
 ///     Application.Init();
-///     var win = new Window ($"Example App ({Application.QuitKey} to quit)");
+///     var win = new Window()
+///     {
+///         Title = $"Example App ({Application.QuitKey} to quit)"
+///     };
 ///     Application.Run(win);
 ///     win.Dispose();
 ///     Application.Shutdown();
 ///     </code>
 /// </example>
-/// <remarks>TODO: Flush this out.</remarks>
+/// <remarks></remarks>
 public static partial class Application
 {
     /// <summary>Gets all cultures supported by the application without the invariant language.</summary>

From 2939108bfe248475a0ce0a8cd2bbfb86cc4555c2 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Mon, 22 Jul 2024 17:06:21 -0600
Subject: [PATCH 05/33] Added Toplevel to spelling dict

---
 Terminal.sln.DotSettings | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Terminal.sln.DotSettings b/Terminal.sln.DotSettings
index bf87e5ea9..0142f001b 100644
--- a/Terminal.sln.DotSettings
+++ b/Terminal.sln.DotSettings
@@ -405,6 +405,7 @@
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Justifier/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=langword/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Roslynator/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=Toplevel/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=unsynchronized/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=BUGBUG/@EntryIndexedValue">True</s:Boolean>
 </wpf:ResourceDictionary>

From 250050c8a2729846cfd4a43373a18feb92df31fd Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Mon, 22 Jul 2024 17:50:45 -0600
Subject: [PATCH 06/33] Toplevel cleanup

---
 .../Application/Application.Initialization.cs |   1 -
 .../Application/Application.Keyboard.cs       |   3 +
 Terminal.Gui/Application/Application.cs       | 218 ------------------
 Terminal.Gui/Views/Toplevel.cs                |  55 ++---
 4 files changed, 28 insertions(+), 249 deletions(-)

diff --git a/Terminal.Gui/Application/Application.Initialization.cs b/Terminal.Gui/Application/Application.Initialization.cs
index a971850e3..16b7b83d4 100644
--- a/Terminal.Gui/Application/Application.Initialization.cs
+++ b/Terminal.Gui/Application/Application.Initialization.cs
@@ -40,7 +40,6 @@ public static partial class Application // Initialization (Init/Shutdown)
     internal static bool _initialized;
     internal static int _mainThreadId = -1;
 
-
     // INTERNAL function for initializing an app with a Toplevel factory object, driver, and mainloop.
     //
     // Called from:
diff --git a/Terminal.Gui/Application/Application.Keyboard.cs b/Terminal.Gui/Application/Application.Keyboard.cs
index e8d698286..703a84982 100644
--- a/Terminal.Gui/Application/Application.Keyboard.cs
+++ b/Terminal.Gui/Application/Application.Keyboard.cs
@@ -25,6 +25,7 @@ public static partial class Application // Keyboard handling
 
     private static void OnAlternateForwardKeyChanged (KeyChangedEventArgs e)
     {
+        // TODO: The fact Top has it's own AlternateForwardKey and events is needlessly complex. Remove it.
         foreach (Toplevel top in _topLevels.ToArray ())
         {
             top.OnAlternateForwardKeyChanged (e);
@@ -52,6 +53,7 @@ public static partial class Application // Keyboard handling
 
     private static void OnAlternateBackwardKeyChanged (KeyChangedEventArgs oldKey)
     {
+        // TODO: The fact Top has it's own AlternateBackwardKey and events is needlessly complex. Remove it.
         foreach (Toplevel top in _topLevels.ToArray ())
         {
             top.OnAlternateBackwardKeyChanged (oldKey);
@@ -79,6 +81,7 @@ public static partial class Application // Keyboard handling
 
     private static void OnQuitKeyChanged (KeyChangedEventArgs e)
     {
+        // TODO: The fact Top has it's own QuitKey and events is needlessly complex. Remove it.
         // Duplicate the list so if it changes during enumeration we're safe
         foreach (Toplevel top in _topLevels.ToArray ())
         {
diff --git a/Terminal.Gui/Application/Application.cs b/Terminal.Gui/Application/Application.cs
index 202b66044..3b4c9d9f7 100644
--- a/Terminal.Gui/Application/Application.cs
+++ b/Terminal.Gui/Application/Application.cs
@@ -137,232 +137,14 @@ public static partial class Application
         SynchronizationContext.SetSynchronizationContext (null);
     }
 
-    // When `End ()` is called, it is possible `RunState.Toplevel` is a different object than `Top`.
-    // This field is set in `End` in this case so that `Begin` correctly sets `Top`.
-
-    // TODO: Determine if this is really needed. The only code that calls WakeUp I can find
-    // is ProgressBarStyles, and it's not clear it needs to.
-
-    #region Toplevel handling
-
-    /// <summary>Holds the stack of TopLevel views.</summary>
-
-    // BUGBUG: Technically, this is not the full lst of TopLevels. There be dragons here, e.g. see how Toplevel.Id is used. What
-    // about TopLevels that are just a SubView of another View?
-    internal static readonly Stack<Toplevel> _topLevels = new ();
-
-    /// <summary>The <see cref="Toplevel"/> object used for the application on startup (<seealso cref="Application.Top"/>)</summary>
-    /// <value>The top.</value>
-    public static Toplevel? Top { get; private set; }
-
-    /// <summary>
-    ///     The current <see cref="Toplevel"/> object. This is updated in <see cref="Application.Begin"/> enters and leaves to
-    ///     point to the current
-    ///     <see cref="Toplevel"/> .
-    /// </summary>
-    /// <remarks>
-    ///     Only relevant in scenarios where <see cref="Toplevel.IsOverlappedContainer"/> is <see langword="true"/>.
-    /// </remarks>
-    /// <value>The current.</value>
-    public static Toplevel? Current { get; private set; }
-
-    private static void EnsureModalOrVisibleAlwaysOnTop (Toplevel topLevel)
-    {
-        if (!topLevel.Running
-            || (topLevel == Current && topLevel.Visible)
-            || OverlappedTop == null
-            || _topLevels.Peek ().Modal)
-        {
-            return;
-        }
-
-        foreach (Toplevel? top in _topLevels.Reverse ())
-        {
-            if (top.Modal && top != Current)
-            {
-                MoveCurrent (top);
-
-                return;
-            }
-        }
-
-        if (!topLevel.Visible && topLevel == Current)
-        {
-            OverlappedMoveNext ();
-        }
-    }
-
 #nullable enable
-    private static Toplevel? FindDeepestTop (Toplevel start, in Point location)
-    {
-        if (!start.Frame.Contains (location))
-        {
-            return null;
-        }
-
-        if (_topLevels is { Count: > 0 })
-        {
-            int rx = location.X - start.Frame.X;
-            int ry = location.Y - start.Frame.Y;
-
-            foreach (Toplevel? t in _topLevels)
-            {
-                if (t != Current)
-                {
-                    if (t != start && t.Visible && t.Frame.Contains (rx, ry))
-                    {
-                        start = t;
-
-                        break;
-                    }
-                }
-            }
-        }
-
-        return start;
-    }
 #nullable restore
 
-    private static View FindTopFromView (View view)
-    {
-        View top = view?.SuperView is { } && view?.SuperView != Top
-                       ? view.SuperView
-                       : view;
-
-        while (top?.SuperView is { } && top?.SuperView != Top)
-        {
-            top = top.SuperView;
-        }
-
-        return top;
-    }
-
 #nullable enable
 
     // Only return true if the Current has changed.
-    private static bool MoveCurrent (Toplevel top)
-    {
-        // The Current is modal and the top is not modal Toplevel then
-        // the Current must be moved above the first not modal Toplevel.
-        if (OverlappedTop is { }
-            && top != OverlappedTop
-            && top != Current
-            && Current?.Modal == true
-            && !_topLevels.Peek ().Modal)
-        {
-            lock (_topLevels)
-            {
-                _topLevels.MoveTo (Current, 0, new ToplevelEqualityComparer ());
-            }
-
-            var index = 0;
-            Toplevel? [] savedToplevels = _topLevels.ToArray ();
-
-            foreach (Toplevel? t in savedToplevels)
-            {
-                if (!t!.Modal && t != Current && t != top && t != savedToplevels [index])
-                {
-                    lock (_topLevels)
-                    {
-                        _topLevels.MoveTo (top, index, new ToplevelEqualityComparer ());
-                    }
-                }
-
-                index++;
-            }
-
-            return false;
-        }
-
-        // The Current and the top are both not running Toplevel then
-        // the top must be moved above the first not running Toplevel.
-        if (OverlappedTop is { }
-            && top != OverlappedTop
-            && top != Current
-            && Current?.Running == false
-            && top?.Running == false)
-        {
-            lock (_topLevels)
-            {
-                _topLevels.MoveTo (Current, 0, new ToplevelEqualityComparer ());
-            }
-
-            var index = 0;
-
-            foreach (Toplevel? t in _topLevels.ToArray ())
-            {
-                if (!t.Running && t != Current && index > 0)
-                {
-                    lock (_topLevels)
-                    {
-                        _topLevels.MoveTo (top, index - 1, new ToplevelEqualityComparer ());
-                    }
-                }
-
-                index++;
-            }
-
-            return false;
-        }
-
-        if ((OverlappedTop is { } && top?.Modal == true && _topLevels.Peek () != top)
-            || (OverlappedTop is { } && Current != OverlappedTop && Current?.Modal == false && top == OverlappedTop)
-            || (OverlappedTop is { } && Current?.Modal == false && top != Current)
-            || (OverlappedTop is { } && Current?.Modal == true && top == OverlappedTop))
-        {
-            lock (_topLevels)
-            {
-                _topLevels.MoveTo (top, 0, new ToplevelEqualityComparer ());
-                Current = top;
-            }
-        }
-
-        return true;
-    }
 #nullable restore
 
-    /// <summary>Invoked when the terminal's size changed. The new size of the terminal is provided.</summary>
-    /// <remarks>
-    ///     Event handlers can set <see cref="SizeChangedEventArgs.Cancel"/> to <see langword="true"/> to prevent
-    ///     <see cref="Application"/> from changing it's size to match the new terminal size.
-    /// </remarks>
-    public static event EventHandler<SizeChangedEventArgs> SizeChanging;
-
-    /// <summary>
-    ///     Called when the application's size changes. Sets the size of all <see cref="Toplevel"/>s and fires the
-    ///     <see cref="SizeChanging"/> event.
-    /// </summary>
-    /// <param name="args">The new size.</param>
-    /// <returns><see lanword="true"/>if the size was changed.</returns>
-    public static bool OnSizeChanging (SizeChangedEventArgs args)
-    {
-        SizeChanging?.Invoke (null, args);
-
-        if (args.Cancel || args.Size is null)
-        {
-            return false;
-        }
-
-        foreach (Toplevel t in _topLevels)
-        {
-            t.SetRelativeLayout (args.Size.Value);
-            t.LayoutSubviews ();
-            t.PositionToplevels ();
-            t.OnSizeChanging (new (args.Size));
-
-            if (PositionCursor (t))
-            {
-                Driver.UpdateCursor ();
-            }
-        }
-
-        Refresh ();
-
-        return true;
-    }
-
-    #endregion Toplevel handling
-
     /// <summary>
     ///     Gets a string representation of the Application as rendered by <see cref="Driver"/>.
     /// </summary>
diff --git a/Terminal.Gui/Views/Toplevel.cs b/Terminal.Gui/Views/Toplevel.cs
index 617dfa7fc..32d8f8a89 100644
--- a/Terminal.Gui/Views/Toplevel.cs
+++ b/Terminal.Gui/Views/Toplevel.cs
@@ -6,7 +6,7 @@ namespace Terminal.Gui;
 /// </summary>
 /// <remarks>
 ///     <para>
-///         Toplevels can run as modal (popup) views, started by calling
+///         Toplevel views can run as modal (popup) views, started by calling
 ///         <see cref="Application.Run(Toplevel, Func{Exception, bool})"/>. They return control to the caller when
 ///         <see cref="Application.RequestStop(Toplevel)"/> has been called (which sets the <see cref="Toplevel.Running"/>
 ///         property to <c>false</c>).
@@ -14,7 +14,7 @@ namespace Terminal.Gui;
 ///     <para>
 ///         A Toplevel is created when an application initializes Terminal.Gui by calling <see cref="Application.Init"/>.
 ///         The application Toplevel can be accessed via <see cref="Application.Top"/>. Additional Toplevels can be created
-///         and run (e.g. <see cref="Dialog"/>s. To run a Toplevel, create the <see cref="Toplevel"/> and call
+///         and run (e.g. <see cref="Dialog"/>s). To run a Toplevel, create the <see cref="Toplevel"/> and call
 ///         <see cref="Application.Run(Toplevel, Func{Exception, bool})"/>.
 ///     </para>
 /// </remarks>
@@ -259,32 +259,30 @@ public partial class Toplevel : View
             return;
         }
 
-        if (NeedsDisplay || SubViewNeedsDisplay || LayoutNeeded)
+        if (NeedsDisplay || SubViewNeedsDisplay /*|| LayoutNeeded*/)
         {
-            //Driver.SetAttribute (GetNormalColor ());
-            // TODO: It's bad practice for views to always clear. Defeats the purpose of clipping etc...
             Clear ();
-            LayoutSubviews ();
-            PositionToplevels ();
+            //LayoutSubviews ();
+            //PositionToplevels ();
 
-            if (this == Application.OverlappedTop)
-            {
-                foreach (Toplevel top in Application.OverlappedChildren.AsEnumerable ().Reverse ())
-                {
-                    if (top.Frame.IntersectsWith (Viewport))
-                    {
-                        if (top != this && !top.IsCurrentTop && !OutsideTopFrame (top) && top.Visible)
-                        {
-                            top.SetNeedsLayout ();
-                            top.SetNeedsDisplay (top.Viewport);
-                            top.Draw ();
-                            top.OnRenderLineCanvas ();
-                        }
-                    }
-                }
-            }
+            //if (this == Application.OverlappedTop)
+            //{
+            //    foreach (Toplevel top in Application.OverlappedChildren.AsEnumerable ().Reverse ())
+            //    {
+            //        if (top.Frame.IntersectsWith (Viewport))
+            //        {
+            //            if (top != this && !top.IsCurrentTop && !OutsideTopFrame (top) && top.Visible)
+            //            {
+            //                top.SetNeedsLayout ();
+            //                top.SetNeedsDisplay (top.Viewport);
+            //                top.Draw ();
+            //                top.OnRenderLineCanvas ();
+            //            }
+            //        }
+            //    }
+            //}
 
-            // This should not be here, but in base
+            // BUGBUG: This appears to be a hack to get ScrollBarViews to render correctly.
             foreach (View view in Subviews)
             {
                 if (view.Frame.IntersectsWith (Viewport) && !OutsideTopFrame (this))
@@ -296,12 +294,6 @@ public partial class Toplevel : View
             }
 
             base.OnDrawContent (viewport);
-
-            // This is causing the menus drawn incorrectly if UseSubMenusSingleFrame is true
-            //if (this.MenuBar is { } && this.MenuBar.IsMenuOpen && this.MenuBar.openMenu is { }) {
-            //	// TODO: Hack until we can get compositing working right.
-            //	this.MenuBar.openMenu.Redraw (this.MenuBar.openMenu.Viewport);
-            //}
         }
     }
 
@@ -315,6 +307,9 @@ public partial class Toplevel : View
     ///     Called from <see cref="Application.Begin(Toplevel)"/> before the <see cref="Toplevel"/> redraws for the first
     ///     time.
     /// </summary>
+    /// <remarks>
+    ///     Overrides must call base.OnLoaded() to ensure any Toplevel subviews are initialized properly and the <see cref="Loaded"/> event is raised.
+    /// </remarks>
     public virtual void OnLoaded ()
     {
         IsLoaded = true;

From 47010805cdb3312135da0b3367ebbc1cac54e7e5 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Tue, 23 Jul 2024 09:41:21 -0600
Subject: [PATCH 07/33] Toplevel.cs organization

---
 Terminal.Gui/Views/Toplevel.cs | 708 +++++++++++++++++----------------
 1 file changed, 376 insertions(+), 332 deletions(-)

diff --git a/Terminal.Gui/Views/Toplevel.cs b/Terminal.Gui/Views/Toplevel.cs
index 32d8f8a89..fa526904d 100644
--- a/Terminal.Gui/Views/Toplevel.cs
+++ b/Terminal.Gui/Views/Toplevel.cs
@@ -27,12 +27,45 @@ public partial class Toplevel : View
     /// </summary>
     public Toplevel ()
     {
+        CanFocus = true;
         Arrangement = ViewArrangement.Fixed;
         Width = Dim.Fill ();
         Height = Dim.Fill ();
 
         ColorScheme = Colors.ColorSchemes ["TopLevel"];
 
+        ConfigureKeyBindings ();
+
+        MouseClick += Toplevel_MouseClick;
+    }
+
+    // TODO: IRunnable: Re-implement - Modal means IRunnable, ViewArrangement.Overlapped where modalView.Z > allOtherViews.Max (v = v.Z).
+    /// <summary>
+    ///     Determines whether the <see cref="Toplevel"/> is modal or not. If set to <c>false</c> (the default):
+    ///     <list type="bullet">
+    ///         <item>
+    ///             <description><see cref="View.OnKeyDown"/> events will propagate keys upwards.</description>
+    ///         </item>
+    ///         <item>
+    ///             <description>The Toplevel will act as an embedded view (not a modal/pop-up).</description>
+    ///         </item>
+    ///     </list>
+    ///     If set to <c>true</c>:
+    ///     <list type="bullet">
+    ///         <item>
+    ///             <description><see cref="View.OnKeyDown"/> events will NOT propagate keys upwards.</description>
+    ///         </item>
+    ///         <item>
+    ///             <description>The Toplevel will and look like a modal (pop-up) (e.g. see <see cref="Dialog"/>.</description>
+    ///         </item>
+    ///     </list>
+    /// </summary>
+    public bool Modal { get; set; }
+
+    #region Keyboard & Mouse
+
+    private void ConfigureKeyBindings ()
+    {
         // Things this view knows how to do
         AddCommand (
                     Command.QuitToplevel,
@@ -134,107 +167,19 @@ public partial class Toplevel : View
         KeyBindings.Add (Key.I.WithCtrl, Command.NextView); // Unix
         KeyBindings.Add (Key.B.WithCtrl, Command.PreviousView); // Unix
 #endif
-        MouseClick += Toplevel_MouseClick;
-
-        CanFocus = true;
     }
 
-    private void Toplevel_MouseClick (object sender, MouseEventEventArgs e)
-    {
-        e.Handled = InvokeCommand (Command.HotKey) == true;
-    }
-
-    /// <summary>
-    ///     <see langword="true"/> if was already loaded by the <see cref="Application.Begin(Toplevel)"/>
-    ///     <see langword="false"/>, otherwise.
-    /// </summary>
-    public bool IsLoaded { get; private set; }
-
-    /// <summary>Gets or sets the menu for this Toplevel.</summary>
-    public virtual MenuBar MenuBar { get; set; }
-
-    /// <summary>
-    ///     Determines whether the <see cref="Toplevel"/> is modal or not. If set to <c>false</c> (the default):
-    ///     <list type="bullet">
-    ///         <item>
-    ///             <description><see cref="View.OnKeyDown"/> events will propagate keys upwards.</description>
-    ///         </item>
-    ///         <item>
-    ///             <description>The Toplevel will act as an embedded view (not a modal/pop-up).</description>
-    ///         </item>
-    ///     </list>
-    ///     If set to <c>true</c>:
-    ///     <list type="bullet">
-    ///         <item>
-    ///             <description><see cref="View.OnKeyDown"/> events will NOT propagate keys upwards.</description>
-    ///         </item>
-    ///         <item>
-    ///             <description>The Toplevel will and look like a modal (pop-up) (e.g. see <see cref="Dialog"/>.</description>
-    ///         </item>
-    ///     </list>
-    /// </summary>
-    public bool Modal { get; set; }
-
-    /// <summary>Gets or sets whether the main loop for this <see cref="Toplevel"/> is running or not.</summary>
-    /// <remarks>Setting this property directly is discouraged. Use <see cref="Application.RequestStop"/> instead.</remarks>
-    public bool Running { get; set; }
-
-    /// <summary>Gets or sets the status bar for this Toplevel.</summary>
-    public virtual StatusBar StatusBar { get; set; }
-
-    /// <summary>Invoked when the Toplevel <see cref="RunState"/> becomes the <see cref="Application.Current"/> Toplevel.</summary>
-    public event EventHandler<ToplevelEventArgs> Activate;
-
-    /// <inheritdoc/>
-    public override View Add (View view)
-    {
-        CanFocus = true;
-        AddMenuStatusBar (view);
-        return base.Add (view);
-    }
-
-    /// <summary>
-    ///     Invoked when the last child of the Toplevel <see cref="RunState"/> is closed from by
-    ///     <see cref="Application.End(RunState)"/>.
-    /// </summary>
-    public event EventHandler AllChildClosed;
+    private void Toplevel_MouseClick (object sender, MouseEventEventArgs e) { e.Handled = InvokeCommand (Command.HotKey) == true; }
 
+    // TODO: Deprecate - No need for this at View level; having at Application is sufficient.
     /// <summary>Invoked when the <see cref="Application.AlternateBackwardKey"/> is changed.</summary>
     public event EventHandler<KeyChangedEventArgs> AlternateBackwardKeyChanged;
 
+    // TODO: Deprecate - No need for this at View level; having at Application is sufficient.
     /// <summary>Invoked when the <see cref="Application.AlternateForwardKey"/> is changed.</summary>
     public event EventHandler<KeyChangedEventArgs> AlternateForwardKeyChanged;
 
-    /// <summary>
-    ///     Invoked when a child of the Toplevel <see cref="RunState"/> is closed by
-    ///     <see cref="Application.End(RunState)"/>.
-    /// </summary>
-    public event EventHandler<ToplevelEventArgs> ChildClosed;
-
-    /// <summary>Invoked when a child Toplevel's <see cref="RunState"/> has been loaded.</summary>
-    public event EventHandler<ToplevelEventArgs> ChildLoaded;
-
-    /// <summary>Invoked when a cjhild Toplevel's <see cref="RunState"/> has been unloaded.</summary>
-    public event EventHandler<ToplevelEventArgs> ChildUnloaded;
-
-    /// <summary>Invoked when the Toplevel's <see cref="RunState"/> is closed by <see cref="Application.End(RunState)"/>.</summary>
-    public event EventHandler<ToplevelEventArgs> Closed;
-
-    /// <summary>
-    ///     Invoked when the Toplevel's <see cref="RunState"/> is being closed by
-    ///     <see cref="Application.RequestStop(Toplevel)"/>.
-    /// </summary>
-    public event EventHandler<ToplevelClosingEventArgs> Closing;
-
-    /// <summary>Invoked when the Toplevel<see cref="RunState"/> ceases to be the <see cref="Application.Current"/> Toplevel.</summary>
-    public event EventHandler<ToplevelEventArgs> Deactivate;
-
-    /// <summary>
-    ///     Invoked when the <see cref="Toplevel"/> <see cref="RunState"/> has begun to be loaded. A Loaded event handler
-    ///     is a good place to finalize initialization before calling <see cref="Application.RunLoop(RunState)"/>.
-    /// </summary>
-    public event EventHandler Loaded;
-
+    // TODO: Deprecate - No need for this at View level; having at Application is sufficient.
     /// <summary>Virtual method to invoke the <see cref="AlternateBackwardKeyChanged"/> event.</summary>
     /// <param name="e"></param>
     public virtual void OnAlternateBackwardKeyChanged (KeyChangedEventArgs e)
@@ -243,6 +188,7 @@ public partial class Toplevel : View
         AlternateBackwardKeyChanged?.Invoke (this, e);
     }
 
+    // TODO: Deprecate - No need for this at View level; having at Application is sufficient.
     /// <summary>Virtual method to invoke the <see cref="AlternateForwardKeyChanged"/> event.</summary>
     /// <param name="e"></param>
     public virtual void OnAlternateForwardKeyChanged (KeyChangedEventArgs e)
@@ -251,77 +197,6 @@ public partial class Toplevel : View
         AlternateForwardKeyChanged?.Invoke (this, e);
     }
 
-    /// <inheritdoc/>
-    public override void OnDrawContent (Rectangle viewport)
-    {
-        if (!Visible)
-        {
-            return;
-        }
-
-        if (NeedsDisplay || SubViewNeedsDisplay /*|| LayoutNeeded*/)
-        {
-            Clear ();
-            //LayoutSubviews ();
-            //PositionToplevels ();
-
-            //if (this == Application.OverlappedTop)
-            //{
-            //    foreach (Toplevel top in Application.OverlappedChildren.AsEnumerable ().Reverse ())
-            //    {
-            //        if (top.Frame.IntersectsWith (Viewport))
-            //        {
-            //            if (top != this && !top.IsCurrentTop && !OutsideTopFrame (top) && top.Visible)
-            //            {
-            //                top.SetNeedsLayout ();
-            //                top.SetNeedsDisplay (top.Viewport);
-            //                top.Draw ();
-            //                top.OnRenderLineCanvas ();
-            //            }
-            //        }
-            //    }
-            //}
-
-            // BUGBUG: This appears to be a hack to get ScrollBarViews to render correctly.
-            foreach (View view in Subviews)
-            {
-                if (view.Frame.IntersectsWith (Viewport) && !OutsideTopFrame (this))
-                {
-                    //view.SetNeedsLayout ();
-                    view.SetNeedsDisplay ();
-                    view.SetSubViewNeedsDisplay ();
-                }
-            }
-
-            base.OnDrawContent (viewport);
-        }
-    }
-
-    /// <inheritdoc/>
-    public override bool OnEnter (View view) { return MostFocused?.OnEnter (view) ?? base.OnEnter (view); }
-
-    /// <inheritdoc/>
-    public override bool OnLeave (View view) { return MostFocused?.OnLeave (view) ?? base.OnLeave (view); }
-
-    /// <summary>
-    ///     Called from <see cref="Application.Begin(Toplevel)"/> before the <see cref="Toplevel"/> redraws for the first
-    ///     time.
-    /// </summary>
-    /// <remarks>
-    ///     Overrides must call base.OnLoaded() to ensure any Toplevel subviews are initialized properly and the <see cref="Loaded"/> event is raised.
-    /// </remarks>
-    public virtual void OnLoaded ()
-    {
-        IsLoaded = true;
-
-        foreach (Toplevel tl in Subviews.Where (v => v is Toplevel))
-        {
-            tl.OnLoaded ();
-        }
-
-        Loaded?.Invoke (this, EventArgs.Empty);
-    }
-
     /// <summary>Virtual method to invoke the <see cref="QuitKeyChanged"/> event.</summary>
     /// <param name="e"></param>
     public virtual void OnQuitKeyChanged (KeyChangedEventArgs e)
@@ -330,120 +205,29 @@ public partial class Toplevel : View
         QuitKeyChanged?.Invoke (this, e);
     }
 
-    /// <inheritdoc/>
-    public override Point? PositionCursor ()
-    {
-        if (!IsOverlappedContainer)
-        {
-            if (Focused is null)
-            {
-                EnsureFocus ();
-            }
-
-            return null;
-        }
-
-        // This code path only happens when the Toplevel is an Overlapped container
-
-        if (Focused is null)
-        {
-            // TODO: this is an Overlapped hack
-            foreach (Toplevel top in Application.OverlappedChildren)
-            {
-                if (top != this && top.Visible)
-                {
-                    top.SetFocus ();
-
-                    return null;
-                }
-            }
-        }
-
-        var cursor2 = base.PositionCursor ();
-
-        return null; 
-    }
-
-    /// <summary>
-    ///     Adjusts the location and size of <paramref name="top"/> within this Toplevel. Virtual method enabling
-    ///     implementation of specific positions for inherited <see cref="Toplevel"/> views.
-    /// </summary>
-    /// <param name="top">The Toplevel to adjust.</param>
-    public virtual void PositionToplevel (Toplevel top)
-    {
-
-        View superView = GetLocationEnsuringFullVisibility (
-                                              top,
-                                              top.Frame.X,
-                                              top.Frame.Y,
-                                              out int nx,
-                                              out int ny,
-                                              out StatusBar sb
-                                             );
-
-        if (superView is null)
-        {
-            return;
-        }
-
-        var layoutSubviews = false;
-        var maxWidth = 0;
-
-        if (superView.Margin is { } && superView == top.SuperView)
-        {
-            maxWidth -= superView.GetAdornmentsThickness ().Left + superView.GetAdornmentsThickness ().Right;
-        }
-
-        if ((superView != top || top?.SuperView is { } || (top != Application.Top && top.Modal) || (top?.SuperView is null && top.IsOverlapped))
-            && (top.Frame.X + top.Frame.Width > maxWidth || ny > top.Frame.Y))
-        {
-            if ((top.X is null || top.X is PosAbsolute) && top.Frame.X != nx)
-            {
-                top.X = nx;
-                layoutSubviews = true;
-            }
-
-            if ((top.Y is null || top.Y is PosAbsolute) && top.Frame.Y != ny)
-            {
-                top.Y = ny;
-                layoutSubviews = true;
-            }
-        }
-
-        // TODO: v2 - This is a hack to get the StatusBar to be positioned correctly.
-        if (sb != null
-            && !top.Subviews.Contains (sb)
-            && ny + top.Frame.Height != superView.Frame.Height - (sb.Visible ? 1 : 0)
-            && top.Height is DimFill
-            && -top.Height.GetAnchor (0) < 1)
-        {
-            top.Height = Dim.Fill (sb.Visible ? 1 : 0);
-            layoutSubviews = true;
-        }
-
-        if (superView.LayoutNeeded || layoutSubviews)
-        {
-            superView.LayoutSubviews ();
-        }
-
-        if (LayoutNeeded)
-        {
-            LayoutSubviews ();
-        }
-    }
-
     /// <summary>Invoked when the <see cref="Application.QuitKey"/> is changed.</summary>
     public event EventHandler<KeyChangedEventArgs> QuitKeyChanged;
 
-    /// <summary>
-    ///     Invoked when the <see cref="Toplevel"/> main loop has started it's first iteration. Subscribe to this event to
-    ///     perform tasks when the <see cref="Toplevel"/> has been laid out and focus has been set. changes.
-    ///     <para>
-    ///         A Ready event handler is a good place to finalize initialization after calling
-    ///         <see cref="Application.Run(Toplevel, Func{Exception, bool})"/> on this <see cref="Toplevel"/>.
-    ///     </para>
-    /// </summary>
-    public event EventHandler Ready;
+    #endregion
+
+    #region Subviews
+
+    // TODO: Deprecate - Any view can host a menubar in v2
+    /// <summary>Gets or sets the menu for this Toplevel.</summary>
+    public virtual MenuBar MenuBar { get; set; }
+
+    // TODO: Deprecate - Any view can host a statusbar in v2
+    /// <summary>Gets or sets the status bar for this Toplevel.</summary>
+    public virtual StatusBar StatusBar { get; set; }
+
+    /// <inheritdoc/>
+    public override View Add (View view)
+    {
+        CanFocus = true;
+        AddMenuStatusBar (view);
+
+        return base.Add (view);
+    }
 
     /// <inheritdoc/>
     public override View Remove (View view)
@@ -470,6 +254,125 @@ public partial class Toplevel : View
         base.RemoveAll ();
     }
 
+    internal void AddMenuStatusBar (View view)
+    {
+        if (view is MenuBar)
+        {
+            MenuBar = view as MenuBar;
+        }
+
+        if (view is StatusBar)
+        {
+            StatusBar = view as StatusBar;
+        }
+    }
+
+    internal void RemoveMenuStatusBar (View view)
+    {
+        if (view is MenuBar)
+        {
+            MenuBar?.Dispose ();
+            MenuBar = null;
+        }
+
+        if (view is StatusBar)
+        {
+            StatusBar?.Dispose ();
+            StatusBar = null;
+        }
+    }
+
+    // TODO: Overlapped - Rename to AllSubviewsClosed - Move to View?
+    /// <summary>
+    ///     Invoked when the last child of the Toplevel <see cref="RunState"/> is closed from by
+    ///     <see cref="Application.End(RunState)"/>.
+    /// </summary>
+    public event EventHandler AllChildClosed;
+
+    // TODO: Overlapped - Rename to *Subviews* - Move to View?
+    /// <summary>
+    ///     Invoked when a child of the Toplevel <see cref="RunState"/> is closed by
+    ///     <see cref="Application.End(RunState)"/>.
+    /// </summary>
+    public event EventHandler<ToplevelEventArgs> ChildClosed;
+
+    // TODO: Overlapped - Rename to *Subviews* - Move to View?
+    /// <summary>Invoked when a child Toplevel's <see cref="RunState"/> has been loaded.</summary>
+    public event EventHandler<ToplevelEventArgs> ChildLoaded;
+
+    // TODO: Overlapped - Rename to *Subviews* - Move to View?
+    /// <summary>Invoked when a cjhild Toplevel's <see cref="RunState"/> has been unloaded.</summary>
+    public event EventHandler<ToplevelEventArgs> ChildUnloaded;
+
+    #endregion
+
+    #region Life Cycle
+
+    // TODO: IRunnable: Re-implement as a property on IRunnable
+    /// <summary>Gets or sets whether the main loop for this <see cref="Toplevel"/> is running or not.</summary>
+    /// <remarks>Setting this property directly is discouraged. Use <see cref="Application.RequestStop"/> instead.</remarks>
+    public bool Running { get; set; }
+
+    // TODO: IRunnable: Re-implement in IRunnable
+    /// <summary>
+    ///     <see langword="true"/> if was already loaded by the <see cref="Application.Begin(Toplevel)"/>
+    ///     <see langword="false"/>, otherwise.
+    /// </summary>
+    public bool IsLoaded { get; private set; }
+
+    // TODO: IRunnable: Re-implement as an event on IRunnable; IRunnable.Activating/Activate
+    /// <summary>Invoked when the Toplevel <see cref="RunState"/> becomes the <see cref="Application.Current"/> Toplevel.</summary>
+    public event EventHandler<ToplevelEventArgs> Activate;
+
+    // TODO: IRunnable: Re-implement as an event on IRunnable; IRunnable.Deactivating/Deactivate?
+    /// <summary>Invoked when the Toplevel<see cref="RunState"/> ceases to be the <see cref="Application.Current"/> Toplevel.</summary>
+    public event EventHandler<ToplevelEventArgs> Deactivate;
+
+    /// <summary>Invoked when the Toplevel's <see cref="RunState"/> is closed by <see cref="Application.End(RunState)"/>.</summary>
+    public event EventHandler<ToplevelEventArgs> Closed;
+
+    /// <summary>
+    ///     Invoked when the Toplevel's <see cref="RunState"/> is being closed by
+    ///     <see cref="Application.RequestStop(Toplevel)"/>.
+    /// </summary>
+    public event EventHandler<ToplevelClosingEventArgs> Closing;
+
+    /// <summary>
+    ///     Invoked when the <see cref="Toplevel"/> <see cref="RunState"/> has begun to be loaded. A Loaded event handler
+    ///     is a good place to finalize initialization before calling <see cref="Application.RunLoop(RunState)"/>.
+    /// </summary>
+    public event EventHandler Loaded;
+
+    /// <summary>
+    ///     Called from <see cref="Application.Begin(Toplevel)"/> before the <see cref="Toplevel"/> redraws for the first
+    ///     time.
+    /// </summary>
+    /// <remarks>
+    ///     Overrides must call base.OnLoaded() to ensure any Toplevel subviews are initialized properly and the
+    ///     <see cref="Loaded"/> event is raised.
+    /// </remarks>
+    public virtual void OnLoaded ()
+    {
+        IsLoaded = true;
+
+        foreach (Toplevel tl in Subviews.Where (v => v is Toplevel))
+        {
+            tl.OnLoaded ();
+        }
+
+        Loaded?.Invoke (this, EventArgs.Empty);
+    }
+
+    /// <summary>
+    ///     Invoked when the <see cref="Toplevel"/> main loop has started it's first iteration. Subscribe to this event to
+    ///     perform tasks when the <see cref="Toplevel"/> has been laid out and focus has been set. changes.
+    ///     <para>
+    ///         A Ready event handler is a good place to finalize initialization after calling
+    ///         <see cref="Application.Run(Toplevel, Func{Exception, bool})"/> on this <see cref="Toplevel"/>.
+    ///     </para>
+    /// </summary>
+    public event EventHandler Ready;
+
     /// <summary>
     ///     Stops and closes this <see cref="Toplevel"/>. If this Toplevel is the top-most Toplevel,
     ///     <see cref="Application.RequestStop(Toplevel)"/> will be called, causing the application to exit.
@@ -527,6 +430,14 @@ public partial class Toplevel : View
         }
     }
 
+    /// <summary>
+    ///     Invoked when the Toplevel <see cref="RunState"/> has been unloaded. A Unloaded event handler is a good place
+    ///     to dispose objects after calling <see cref="Application.End(RunState)"/>.
+    /// </summary>
+    public event EventHandler Unloaded;
+
+    internal virtual void OnActivate (Toplevel deactivated) { Activate?.Invoke (this, new (deactivated)); }
+
     /// <summary>
     ///     Stops and closes the <see cref="Toplevel"/> specified by <paramref name="top"/>. If <paramref name="top"/> is
     ///     the top-most Toplevel, <see cref="Application.RequestStop(Toplevel)"/> will be called, causing the application to
@@ -535,29 +446,6 @@ public partial class Toplevel : View
     /// <param name="top">The Toplevel to request stop.</param>
     public virtual void RequestStop (Toplevel top) { top.RequestStop (); }
 
-    /// <summary>Invoked when the terminal has been resized. The new <see cref="Size"/> of the terminal is provided.</summary>
-    public event EventHandler<SizeChangedEventArgs> SizeChanging;
-
-    /// <summary>
-    ///     Invoked when the Toplevel <see cref="RunState"/> has been unloaded. A Unloaded event handler is a good place
-    ///     to dispose objects after calling <see cref="Application.End(RunState)"/>.
-    /// </summary>
-    public event EventHandler Unloaded;
-
-    internal void AddMenuStatusBar (View view)
-    {
-        if (view is MenuBar)
-        {
-            MenuBar = view as MenuBar;
-        }
-
-        if (view is StatusBar)
-        {
-            StatusBar = view as StatusBar;
-        }
-    }
-
-    internal virtual void OnActivate (Toplevel deactivated) { Activate?.Invoke (this, new ToplevelEventArgs (deactivated)); }
     internal virtual void OnAllChildClosed () { AllChildClosed?.Invoke (this, EventArgs.Empty); }
 
     internal virtual void OnChildClosed (Toplevel top)
@@ -567,12 +455,12 @@ public partial class Toplevel : View
             SetSubViewNeedsDisplay ();
         }
 
-        ChildClosed?.Invoke (this, new ToplevelEventArgs (top));
+        ChildClosed?.Invoke (this, new (top));
     }
 
-    internal virtual void OnChildLoaded (Toplevel top) { ChildLoaded?.Invoke (this, new ToplevelEventArgs (top)); }
-    internal virtual void OnChildUnloaded (Toplevel top) { ChildUnloaded?.Invoke (this, new ToplevelEventArgs (top)); }
-    internal virtual void OnClosed (Toplevel top) { Closed?.Invoke (this, new ToplevelEventArgs (top)); }
+    internal virtual void OnChildLoaded (Toplevel top) { ChildLoaded?.Invoke (this, new (top)); }
+    internal virtual void OnChildUnloaded (Toplevel top) { ChildUnloaded?.Invoke (this, new (top)); }
+    internal virtual void OnClosed (Toplevel top) { Closed?.Invoke (this, new (top)); }
 
     internal virtual bool OnClosing (ToplevelClosingEventArgs ev)
     {
@@ -581,7 +469,7 @@ public partial class Toplevel : View
         return ev.Cancel;
     }
 
-    internal virtual void OnDeactivate (Toplevel activated) { Deactivate?.Invoke (this, new ToplevelEventArgs (activated)); }
+    internal virtual void OnDeactivate (Toplevel activated) { Deactivate?.Invoke (this, new (activated)); }
 
     /// <summary>
     ///     Called from <see cref="Application.RunLoop"/> after the <see cref="Toplevel"/> has entered the first iteration
@@ -597,9 +485,6 @@ public partial class Toplevel : View
         Ready?.Invoke (this, EventArgs.Empty);
     }
 
-    // TODO: Make cancelable?
-    internal virtual void OnSizeChanging (SizeChangedEventArgs size) { SizeChanging?.Invoke (this, size); }
-
     /// <summary>Called from <see cref="Application.End(RunState)"/> before the <see cref="Toplevel"/> is disposed.</summary>
     internal virtual void OnUnloaded ()
     {
@@ -611,34 +496,78 @@ public partial class Toplevel : View
         Unloaded?.Invoke (this, EventArgs.Empty);
     }
 
-    // TODO: v2 - Not sure this is needed anymore.
-    internal void PositionToplevels ()
+    private void QuitToplevel ()
     {
-        PositionToplevel (this);
-
-        foreach (View top in Subviews)
+        if (Application.OverlappedTop is { })
         {
-            if (top is Toplevel)
+            RequestStop (this);
+        }
+        else
+        {
+            Application.RequestStop ();
+        }
+    }
+
+    #endregion
+
+    #region Draw
+
+    /// <inheritdoc/>
+    public override void OnDrawContent (Rectangle viewport)
+    {
+        if (!Visible)
+        {
+            return;
+        }
+
+        if (NeedsDisplay || SubViewNeedsDisplay /*|| LayoutNeeded*/)
+        {
+            Clear ();
+
+            //LayoutSubviews ();
+            //PositionToplevels ();
+
+            //if (this == Application.OverlappedTop)
+            //{
+            //    foreach (Toplevel top in Application.OverlappedChildren.AsEnumerable ().Reverse ())
+            //    {
+            //        if (top.Frame.IntersectsWith (Viewport))
+            //        {
+            //            if (top != this && !top.IsCurrentTop && !OutsideTopFrame (top) && top.Visible)
+            //            {
+            //                top.SetNeedsLayout ();
+            //                top.SetNeedsDisplay (top.Viewport);
+            //                top.Draw ();
+            //                top.OnRenderLineCanvas ();
+            //            }
+            //        }
+            //    }
+            //}
+
+            // BUGBUG: This appears to be a hack to get ScrollBarViews to render correctly.
+            foreach (View view in Subviews)
             {
-                PositionToplevel ((Toplevel)top);
+                if (view.Frame.IntersectsWith (Viewport) && !OutsideTopFrame (this))
+                {
+                    //view.SetNeedsLayout ();
+                    view.SetNeedsDisplay ();
+                    view.SetSubViewNeedsDisplay ();
+                }
             }
+
+            base.OnDrawContent (viewport);
         }
     }
 
-    internal void RemoveMenuStatusBar (View view)
-    {
-        if (view is MenuBar)
-        {
-            MenuBar?.Dispose ();
-            MenuBar = null;
-        }
+    #endregion
 
-        if (view is StatusBar)
-        {
-            StatusBar?.Dispose ();
-            StatusBar = null;
-        }
-    }
+    #region Focus
+
+    /// <inheritdoc/>
+    public override bool OnEnter (View view) { return MostFocused?.OnEnter (view) ?? base.OnEnter (view); }
+
+    /// <inheritdoc/>
+    public override bool OnLeave (View view) { return MostFocused?.OnLeave (view) ?? base.OnLeave (view); }
 
     private void FocusNearestView (IEnumerable<View> views, NavigationDirection direction)
     {
@@ -785,6 +714,117 @@ public partial class Toplevel : View
         }
     }
 
+    #endregion
+
+    #region Size / Position Management
+
+    // TODO: Make cancelable?
+    internal virtual void OnSizeChanging (SizeChangedEventArgs size) { SizeChanging?.Invoke (this, size); }
+
+    /// <inheritdoc/>
+    public override Point? PositionCursor ()
+    {
+        if (!IsOverlappedContainer)
+        {
+            if (Focused is null)
+            {
+                EnsureFocus ();
+            }
+
+            return null;
+        }
+
+        // This code path only happens when the Toplevel is an Overlapped container
+
+        if (Focused is null)
+        {
+            // TODO: this is an Overlapped hack
+            foreach (Toplevel top in Application.OverlappedChildren)
+            {
+                if (top != this && top.Visible)
+                {
+                    top.SetFocus ();
+
+                    return null;
+                }
+            }
+        }
+
+        Point? cursor2 = base.PositionCursor ();
+
+        return null;
+    }
+
+    /// <summary>
+    ///     Adjusts the location and size of <paramref name="top"/> within this Toplevel. Virtual method enabling
+    ///     implementation of specific positions for inherited <see cref="Toplevel"/> views.
+    /// </summary>
+    /// <param name="top">The Toplevel to adjust.</param>
+    public virtual void PositionToplevel (Toplevel top)
+    {
+        View superView = GetLocationEnsuringFullVisibility (
+                                                            top,
+                                                            top.Frame.X,
+                                                            top.Frame.Y,
+                                                            out int nx,
+                                                            out int ny,
+                                                            out StatusBar sb
+                                                           );
+
+        if (superView is null)
+        {
+            return;
+        }
+
+        var layoutSubviews = false;
+        var maxWidth = 0;
+
+        if (superView.Margin is { } && superView == top.SuperView)
+        {
+            maxWidth -= superView.GetAdornmentsThickness ().Left + superView.GetAdornmentsThickness ().Right;
+        }
+
+        if ((superView != top || top?.SuperView is { } || (top != Application.Top && top.Modal) || (top?.SuperView is null && top.IsOverlapped))
+            && (top.Frame.X + top.Frame.Width > maxWidth || ny > top.Frame.Y))
+        {
+            if ((top.X is null || top.X is PosAbsolute) && top.Frame.X != nx)
+            {
+                top.X = nx;
+                layoutSubviews = true;
+            }
+
+            if ((top.Y is null || top.Y is PosAbsolute) && top.Frame.Y != ny)
+            {
+                top.Y = ny;
+                layoutSubviews = true;
+            }
+        }
+
+        // TODO: v2 - This is a hack to get the StatusBar to be positioned correctly.
+        if (sb != null
+            && !top.Subviews.Contains (sb)
+            && ny + top.Frame.Height != superView.Frame.Height - (sb.Visible ? 1 : 0)
+            && top.Height is DimFill
+            && -top.Height.GetAnchor (0) < 1)
+        {
+            top.Height = Dim.Fill (sb.Visible ? 1 : 0);
+            layoutSubviews = true;
+        }
+
+        if (superView.LayoutNeeded || layoutSubviews)
+        {
+            superView.LayoutSubviews ();
+        }
+
+        if (LayoutNeeded)
+        {
+            LayoutSubviews ();
+        }
+    }
+
+    /// <summary>Invoked when the terminal has been resized. The new <see cref="Size"/> of the terminal is provided.</summary>
+    public event EventHandler<SizeChangedEventArgs> SizeChanging;
+
     private bool OutsideTopFrame (Toplevel top)
     {
         if (top.Frame.X > Driver.Cols || top.Frame.Y > Driver.Rows)
@@ -795,17 +835,21 @@ public partial class Toplevel : View
         return false;
     }
 
-    private void QuitToplevel ()
+    // TODO: v2 - Not sure this is needed anymore.
+    internal void PositionToplevels ()
     {
-        if (Application.OverlappedTop is { })
+        PositionToplevel (this);
+
+        foreach (View top in Subviews)
         {
-            RequestStop (this);
-        }
-        else
-        {
-            Application.RequestStop ();
+            if (top is Toplevel)
+            {
+                PositionToplevel ((Toplevel)top);
+            }
         }
     }
+
+    #endregion
 }
 
 /// <summary>

From d44e8d3b81b0d98f9c022d1ef2c8839728c1f9df Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Tue, 23 Jul 2024 09:59:30 -0600
Subject: [PATCH 08/33] More Toplevel.cs organization & docs

---
 Terminal.Gui/Input/Command.cs  |  1 +
 Terminal.Gui/Views/Toplevel.cs | 59 ++++++++++++++++++----------------
 2 files changed, 33 insertions(+), 27 deletions(-)

diff --git a/Terminal.Gui/Input/Command.cs b/Terminal.Gui/Input/Command.cs
index 566cc9336..c6a03606b 100644
--- a/Terminal.Gui/Input/Command.cs
+++ b/Terminal.Gui/Input/Command.cs
@@ -221,6 +221,7 @@ public enum Command
     /// <summary>Pastes the current selection.</summary>
     Paste,
 
+    // TODO: IRunnable - Should be renamed QuitRunnable
     /// <summary>Quit a <see cref="Toplevel"/>.</summary>
     QuitToplevel,
 
diff --git a/Terminal.Gui/Views/Toplevel.cs b/Terminal.Gui/Views/Toplevel.cs
index fa526904d..e14d02509 100644
--- a/Terminal.Gui/Views/Toplevel.cs
+++ b/Terminal.Gui/Views/Toplevel.cs
@@ -39,7 +39,10 @@ public partial class Toplevel : View
         MouseClick += Toplevel_MouseClick;
     }
 
-    // TODO: IRunnable: Re-implement - Modal means IRunnable, ViewArrangement.Overlapped where modalView.Z > allOtherViews.Max (v = v.Z).
+
+    #region Keyboard & Mouse
+
+    // TODO: IRunnable: Re-implement - Modal means IRunnable, ViewArrangement.Overlapped where modalView.Z > allOtherViews.Max (v = v.Z), and exclusive key/mouse input.
     /// <summary>
     ///     Determines whether the <see cref="Toplevel"/> is modal or not. If set to <c>false</c> (the default):
     ///     <list type="bullet">
@@ -62,13 +65,12 @@ public partial class Toplevel : View
     /// </summary>
     public bool Modal { get; set; }
 
-    #region Keyboard & Mouse
-
+    // TODO: Overlapped: Figure out how these keybindings should work.
     private void ConfigureKeyBindings ()
     {
         // Things this view knows how to do
         AddCommand (
-                    Command.QuitToplevel,
+                    Command.QuitToplevel,  // TODO: IRunnable: Rename to Command.Quit to make more generic.
                     () =>
                     {
                         QuitToplevel ();
@@ -77,8 +79,10 @@ public partial class Toplevel : View
                     }
                    );
 
+        /// TODO: Overlapped: Add Command.ShowHide
+        
         AddCommand (
-                    Command.Suspend,
+                    Command.Suspend,    // TODO: Move to Application
                     () =>
                     {
                         Driver.Suspend ();
@@ -89,7 +93,7 @@ public partial class Toplevel : View
                    );
 
         AddCommand (
-                    Command.NextView,
+                    Command.NextView,    // TODO: Figure out how to move this to the View that is at the root of the view hierarchy (currently Application.Top)
                     () =>
                     {
                         MoveNextView ();
@@ -99,7 +103,7 @@ public partial class Toplevel : View
                    );
 
         AddCommand (
-                    Command.PreviousView,
+                    Command.PreviousView,// TODO: Figure out how to move this to the View that is at the root of the view hierarchy (currently Application.Top)
                     () =>
                     {
                         MovePreviousView ();
@@ -109,7 +113,7 @@ public partial class Toplevel : View
                    );
 
         AddCommand (
-                    Command.NextViewOrTop,
+                    Command.NextViewOrTop,// TODO: Figure out how to move this to the View that is at the root of the view hierarchy (currently Application.Top)
                     () =>
                     {
                         MoveNextViewOrTop ();
@@ -119,7 +123,7 @@ public partial class Toplevel : View
                    );
 
         AddCommand (
-                    Command.PreviousViewOrTop,
+                    Command.PreviousViewOrTop,// TODO: Figure out how to move this to the View that is at the root of the view hierarchy (currently Application.Top)
                     () =>
                     {
                         MovePreviousViewOrTop ();
@@ -132,7 +136,7 @@ public partial class Toplevel : View
                     Command.Refresh,
                     () =>
                     {
-                        Application.Refresh ();
+                        Application.Refresh (); // TODO: Move to Application
 
                         return true;
                     }
@@ -525,24 +529,25 @@ public partial class Toplevel : View
             Clear ();
 
             //LayoutSubviews ();
-            //PositionToplevels ();
+            PositionToplevels ();
 
-            //if (this == Application.OverlappedTop)
-            //{
-            //    foreach (Toplevel top in Application.OverlappedChildren.AsEnumerable ().Reverse ())
-            //    {
-            //        if (top.Frame.IntersectsWith (Viewport))
-            //        {
-            //            if (top != this && !top.IsCurrentTop && !OutsideTopFrame (top) && top.Visible)
-            //            {
-            //                top.SetNeedsLayout ();
-            //                top.SetNeedsDisplay (top.Viewport);
-            //                top.Draw ();
-            //                top.OnRenderLineCanvas ();
-            //            }
-            //        }
-            //    }
-            //}
+            if (this == Application.OverlappedTop)
+            {
+                // This enables correct draw behavior when switching between overlapped subviews
+                foreach (Toplevel top in Application.OverlappedChildren.AsEnumerable ().Reverse ())
+                {
+                    if (top.Frame.IntersectsWith (Viewport))
+                    {
+                        if (top != this && !top.IsCurrentTop && !OutsideTopFrame (top) && top.Visible)
+                        {
+                            top.SetNeedsLayout ();
+                            top.SetNeedsDisplay (top.Viewport);
+                            top.Draw ();
+                            top.OnRenderLineCanvas ();
+                        }
+                    }
+                }
+            }
 
             // BUGBUG: This appears to be a hack to get ScrollBarViews to render correctly.
             foreach (View view in Subviews)

From d813b1f137c87c86271d71539285cc64343b1826 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Tue, 23 Jul 2024 14:19:57 -0600
Subject: [PATCH 09/33] Fixed dumb enum cast in KeyBinding code

---
 Terminal.Gui/Application/Application.Keyboard.cs | 3 ++-
 Terminal.Gui/Input/Command.cs                    | 4 +++-
 Terminal.Gui/Input/KeyBindingScope.cs            | 2 +-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/Terminal.Gui/Application/Application.Keyboard.cs b/Terminal.Gui/Application/Application.Keyboard.cs
index 703a84982..59fecc14a 100644
--- a/Terminal.Gui/Application/Application.Keyboard.cs
+++ b/Terminal.Gui/Application/Application.Keyboard.cs
@@ -144,7 +144,8 @@ public static partial class Application // Keyboard handling
         {
             foreach (View view in binding.Value)
             {
-                if (view is {} && view.KeyBindings.TryGet (binding.Key, (KeyBindingScope)0xFFFF, out KeyBinding kb))
+                if (view is { }
+                    && view.KeyBindings.TryGet (binding.Key, KeyBindingScope.Focused | KeyBindingScope.HotKey | KeyBindingScope.Application, out KeyBinding kb))
                 {
                     //bool? handled = view.InvokeCommands (kb.Commands, binding.Key, kb);
                     bool? handled = view?.OnInvokingKeyBindings (keyEvent, kb.Scope);
diff --git a/Terminal.Gui/Input/Command.cs b/Terminal.Gui/Input/Command.cs
index c6a03606b..42dcb16e6 100644
--- a/Terminal.Gui/Input/Command.cs
+++ b/Terminal.Gui/Input/Command.cs
@@ -221,10 +221,12 @@ public enum Command
     /// <summary>Pastes the current selection.</summary>
     Paste,
 
-    // TODO: IRunnable - Should be renamed QuitRunnable
+    /// TODO: IRunnable: Rename to Command.Quit to make more generic.
     /// <summary>Quit a <see cref="Toplevel"/>.</summary>
     QuitToplevel,
 
+    /// TODO: Overlapped: Add Command.ShowHide
+
     /// <summary>Suspend an application (Only implemented in <see cref="CursesDriver"/>).</summary>
     Suspend,
 
diff --git a/Terminal.Gui/Input/KeyBindingScope.cs b/Terminal.Gui/Input/KeyBindingScope.cs
index 0c75299c7..633e6d7b0 100644
--- a/Terminal.Gui/Input/KeyBindingScope.cs
+++ b/Terminal.Gui/Input/KeyBindingScope.cs
@@ -45,5 +45,5 @@ public enum KeyBindingScope
     ///         any of its subviews, and if the key was not bound to a <see cref="View.HotKey"/>.
     ///     </para>
     /// </remarks>
-    Application = 4
+    Application = 4,
 }

From fe5cbe4df3192d22474f3f0fd834004dc3d84711 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Tue, 23 Jul 2024 14:42:50 -0600
Subject: [PATCH 10/33] More Toplevel.cs organization & docs

---
 Terminal.Gui/Application/Application.Keyboard.cs | 9 +++++++--
 Terminal.Gui/Application/Application.Run.cs      | 1 +
 Terminal.Gui/Application/Application.Toplevel.cs | 2 +-
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/Terminal.Gui/Application/Application.Keyboard.cs b/Terminal.Gui/Application/Application.Keyboard.cs
index 59fecc14a..009d8c425 100644
--- a/Terminal.Gui/Application/Application.Keyboard.cs
+++ b/Terminal.Gui/Application/Application.Keyboard.cs
@@ -230,9 +230,14 @@ public static partial class Application // Keyboard handling
     ///     This is an internal method used by the <see cref="View"/> class to add Application key bindings.
     /// </remarks>
     /// <param name="key">The key being bound.</param>
-    /// <param name="view">The view that is bound to the key.</param>
-    internal static void AddKeyBinding (Key key, View view)
+    /// <param name="view">The view that is bound to the key. If <see langword="null"/>, <see cref="Application.Current"/> will be used.</param>
+    internal static void AddKeyBinding (Key key, [CanBeNull] View view)
     {
+        if (view is null)
+        {
+            view = Current;
+        }
+
         if (!_keyBindings.ContainsKey (key))
         {
             _keyBindings [key] = [];
diff --git a/Terminal.Gui/Application/Application.Run.cs b/Terminal.Gui/Application/Application.Run.cs
index 06c191230..e5e51a0fb 100644
--- a/Terminal.Gui/Application/Application.Run.cs
+++ b/Terminal.Gui/Application/Application.Run.cs
@@ -577,6 +577,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             Iteration?.Invoke (null, new ());
             EnsureModalOrVisibleAlwaysOnTop (state.Toplevel);
 
+            // TODO: Overlapped - Move elsewhere
             if (state.Toplevel != Current)
             {
                 OverlappedTop?.OnDeactivate (state.Toplevel);
diff --git a/Terminal.Gui/Application/Application.Toplevel.cs b/Terminal.Gui/Application/Application.Toplevel.cs
index 6d25f7d02..b08f9e960 100644
--- a/Terminal.Gui/Application/Application.Toplevel.cs
+++ b/Terminal.Gui/Application/Application.Toplevel.cs
@@ -18,7 +18,7 @@ public static partial class Application // Toplevel handling
     ///     <see cref="Toplevel"/> .
     /// </summary>
     /// <remarks>
-    ///     Only relevant in scenarios where <see cref="Toplevel.IsOverlappedContainer"/> is <see langword="true"/>.
+    ///     This will only be distinct from <see cref="Application.Top"/> in scenarios where <see cref="Toplevel.IsOverlappedContainer"/> is <see langword="true"/>.
     /// </remarks>
     /// <value>The current.</value>
     public static Toplevel Current { get; private set; }

From f8e8aff29f46a1e9cbd15a7137313d46f67abb8e Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Tue, 23 Jul 2024 15:36:36 -0600
Subject: [PATCH 11/33] More Toplevel.cs organization & docs

---
 .../Application/Application.Initialization.cs |   3 +
 .../Application/Application.Keyboard.cs       |  46 +++-
 Terminal.Gui/Application/Application.Mouse.cs |   4 +-
 .../Application/Application.Navigation.cs     | 211 ++++++++++++++++++
 .../Application/Application.Overlapped.cs     |   7 +
 Terminal.Gui/Application/Application.Run.cs   |   1 +
 .../Application/Application.Toplevel.cs       |  22 +-
 Terminal.Gui/View/ViewSubViews.cs             |  32 ++-
 Terminal.Gui/Views/Toplevel.cs                |  27 ++-
 Terminal.Gui/Views/ToplevelOverlapped.cs      | 209 -----------------
 10 files changed, 319 insertions(+), 243 deletions(-)
 create mode 100644 Terminal.Gui/Application/Application.Navigation.cs
 create mode 100644 Terminal.Gui/Application/Application.Overlapped.cs

diff --git a/Terminal.Gui/Application/Application.Initialization.cs b/Terminal.Gui/Application/Application.Initialization.cs
index 16b7b83d4..0434eb873 100644
--- a/Terminal.Gui/Application/Application.Initialization.cs
+++ b/Terminal.Gui/Application/Application.Initialization.cs
@@ -1,3 +1,4 @@
+#nullable enable
 using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 
@@ -88,6 +89,8 @@ public static partial class Application // Initialization (Init/Shutdown)
         Load ();
         Apply ();
 
+        AddToplevelKeyBindings ();
+
         // Ignore Configuration for ForceDriver if driverName is specified
         if (!string.IsNullOrEmpty (driverName))
         {
diff --git a/Terminal.Gui/Application/Application.Keyboard.cs b/Terminal.Gui/Application/Application.Keyboard.cs
index 009d8c425..a299a7aee 100644
--- a/Terminal.Gui/Application/Application.Keyboard.cs
+++ b/Terminal.Gui/Application/Application.Keyboard.cs
@@ -1,4 +1,5 @@
-using System.Text.Json.Serialization;
+#nullable enable
+using System.Text.Json.Serialization;
 
 namespace Terminal.Gui;
 
@@ -140,7 +141,7 @@ public static partial class Application // Keyboard handling
 
         // Invoke any global (Application-scoped) KeyBindings.
         // The first view that handles the key will stop the loop.
-        foreach (KeyValuePair<Key, List<View>> binding in _keyBindings.Where (b => b.Key == keyEvent.KeyCode))
+        foreach (KeyValuePair<Key, List<View?>> binding in _keyBindings.Where (b => b.Key == keyEvent.KeyCode))
         {
             foreach (View view in binding.Value)
             {
@@ -154,7 +155,6 @@ public static partial class Application // Keyboard handling
                     {
                         return true;
                     }
-
                 }
             }
         }
@@ -216,12 +216,12 @@ public static partial class Application // Keyboard handling
     /// <summary>
     ///     The <see cref="KeyBindingScope.Application"/> key bindings.
     /// </summary>
-    private static readonly Dictionary<Key, List<View>> _keyBindings = new ();
+    private static readonly Dictionary<Key, List<View?>> _keyBindings = new ();
 
     /// <summary>
     /// Gets the list of <see cref="KeyBindingScope.Application"/> key bindings.
     /// </summary>
-    public static Dictionary<Key, List<View>> GetKeyBindings () { return _keyBindings; }
+    public static Dictionary<Key, List<View?>> GetKeyBindings () { return _keyBindings; }
 
     /// <summary>
     ///     Adds an  <see cref="KeyBindingScope.Application"/> scoped key binding.
@@ -231,13 +231,8 @@ public static partial class Application // Keyboard handling
     /// </remarks>
     /// <param name="key">The key being bound.</param>
     /// <param name="view">The view that is bound to the key. If <see langword="null"/>, <see cref="Application.Current"/> will be used.</param>
-    internal static void AddKeyBinding (Key key, [CanBeNull] View view)
+    internal static void AddKeyBinding (Key key, View? view)
     {
-        if (view is null)
-        {
-            view = Current;
-        }
-
         if (!_keyBindings.ContainsKey (key))
         {
             _keyBindings [key] = [];
@@ -246,6 +241,35 @@ public static partial class Application // Keyboard handling
         _keyBindings [key].Add (view);
     }
 
+    internal static void AddToplevelKeyBindings ()
+    {
+//        // Default keybindings for this view
+//        AddKeyBinding (Application.QuitKey, null);
+//        AddKeyBinding (Key.CursorRight, null);
+//        AddKeyBinding (Key.CursorDown, null);
+//        AddKeyBinding (Key.CursorLeft, null);
+//        AddKeyBinding (Key.CursorUp, null);
+//        AddKeyBinding (Key.Tab, null);
+//        AddKeyBinding (Key.Tab.WithShift, null);
+//        AddKeyBinding (Key.Tab.WithCtrl, null);
+//        AddKeyBinding (Key.Tab.WithShift.WithCtrl, null);
+//        AddKeyBinding (Key.F5, null);
+//        AddKeyBinding (Application.AlternateForwardKey, null); // Needed on Unix
+//        AddKeyBinding (Application.AlternateBackwardKey, null); // Needed on Unix
+
+//        if (Environment.OSVersion.Platform == PlatformID.Unix)
+//        {
+//            AddKeyBinding (Key.Z.WithCtrl, null);
+//        }
+
+//#if UNIX_KEY_BINDINGS
+//        KeyBindings.Add (Key.L.WithCtrl, Command.Refresh); // Unix
+//        KeyBindings.Add (Key.F.WithCtrl, Command.NextView); // Unix
+//        KeyBindings.Add (Key.I.WithCtrl, Command.NextView); // Unix
+//        KeyBindings.Add (Key.B.WithCtrl, Command.PreviousView); // Unix
+//#endif
+    }
+
     /// <summary>
     ///     Gets the list of Views that have <see cref="KeyBindingScope.Application"/> key bindings.
     /// </summary>
diff --git a/Terminal.Gui/Application/Application.Mouse.cs b/Terminal.Gui/Application/Application.Mouse.cs
index 7cad055d5..61fc6d63e 100644
--- a/Terminal.Gui/Application/Application.Mouse.cs
+++ b/Terminal.Gui/Application/Application.Mouse.cs
@@ -1,5 +1,5 @@
-namespace Terminal.Gui;
-
+#nullable enable
+namespace Terminal.Gui;
 public static partial class Application // Mouse handling
 {
     #region Mouse handling
diff --git a/Terminal.Gui/Application/Application.Navigation.cs b/Terminal.Gui/Application/Application.Navigation.cs
new file mode 100644
index 000000000..0bbce67e6
--- /dev/null
+++ b/Terminal.Gui/Application/Application.Navigation.cs
@@ -0,0 +1,211 @@
+namespace Terminal.Gui;
+
+public static partial class Application
+{
+    /// <summary>
+    ///     Gets the list of the Overlapped children which are not modal <see cref="Toplevel"/> from the
+    ///     <see cref="OverlappedTop"/>.
+    /// </summary>
+    public static List<Toplevel> OverlappedChildren
+    {
+        get
+        {
+            if (OverlappedTop is { })
+            {
+                List<Toplevel> _overlappedChildren = new ();
+
+                foreach (Toplevel top in _topLevels)
+                {
+                    if (top != OverlappedTop && !top.Modal)
+                    {
+                        _overlappedChildren.Add (top);
+                    }
+                }
+
+                return _overlappedChildren;
+            }
+
+            return null;
+        }
+    }
+
+#nullable enable
+    /// <summary>
+    ///     The <see cref="Toplevel"/> object used for the application on startup which
+    ///     <see cref="Toplevel.IsOverlappedContainer"/> is true.
+    /// </summary>
+    public static Toplevel? OverlappedTop
+    {
+        get
+        {
+            if (Top is { IsOverlappedContainer: true })
+            {
+                return Top;
+            }
+
+            return null;
+        }
+    }
+#nullable restore
+
+    /// <summary>Brings the superview of the most focused overlapped view is on front.</summary>
+    public static void BringOverlappedTopToFront ()
+    {
+        if (OverlappedTop is { })
+        {
+            return;
+        }
+
+        View top = FindTopFromView (Top?.MostFocused);
+
+        if (top is Toplevel && Top.Subviews.Count > 1 && Top.Subviews [^1] != top)
+        {
+            Top.BringSubviewToFront (top);
+        }
+    }
+
+    /// <summary>Gets the current visible Toplevel overlapped child that matches the arguments pattern.</summary>
+    /// <param name="type">The type.</param>
+    /// <param name="exclude">The strings to exclude.</param>
+    /// <returns>The matched view.</returns>
+    public static Toplevel GetTopOverlappedChild (Type type = null, string [] exclude = null)
+    {
+        if (OverlappedTop is null)
+        {
+            return null;
+        }
+
+        foreach (Toplevel top in OverlappedChildren)
+        {
+            if (type is { } && top.GetType () == type && exclude?.Contains (top.Data.ToString ()) == false)
+            {
+                return top;
+            }
+
+            if ((type is { } && top.GetType () != type) || exclude?.Contains (top.Data.ToString ()) == true)
+            {
+                continue;
+            }
+
+            return top;
+        }
+
+        return null;
+    }
+
+    /// <summary>
+    ///     Move to the next Overlapped child from the <see cref="OverlappedTop"/> and set it as the <see cref="Top"/> if
+    ///     it is not already.
+    /// </summary>
+    /// <param name="top"></param>
+    /// <returns></returns>
+    public static bool MoveToOverlappedChild (Toplevel top)
+    {
+        if (top.Visible && OverlappedTop is { } && Current?.Modal == false)
+        {
+            lock (_topLevels)
+            {
+                _topLevels.MoveTo (top, 0, new ToplevelEqualityComparer ());
+                Current = top;
+            }
+
+            return true;
+        }
+
+        return false;
+    }
+
+    /// <summary>Move to the next Overlapped child from the <see cref="OverlappedTop"/>.</summary>
+    public static void OverlappedMoveNext ()
+    {
+        if (OverlappedTop is { } && !Current.Modal)
+        {
+            lock (_topLevels)
+            {
+                _topLevels.MoveNext ();
+                var isOverlapped = false;
+
+                while (_topLevels.Peek () == OverlappedTop || !_topLevels.Peek ().Visible)
+                {
+                    if (!isOverlapped && _topLevels.Peek () == OverlappedTop)
+                    {
+                        isOverlapped = true;
+                    }
+                    else if (isOverlapped && _topLevels.Peek () == OverlappedTop)
+                    {
+                        MoveCurrent (Top);
+
+                        break;
+                    }
+
+                    _topLevels.MoveNext ();
+                }
+
+                Current = _topLevels.Peek ();
+            }
+        }
+    }
+
+    /// <summary>Move to the previous Overlapped child from the <see cref="OverlappedTop"/>.</summary>
+    public static void OverlappedMovePrevious ()
+    {
+        if (OverlappedTop is { } && !Current.Modal)
+        {
+            lock (_topLevels)
+            {
+                _topLevels.MovePrevious ();
+                var isOverlapped = false;
+
+                while (_topLevels.Peek () == OverlappedTop || !_topLevels.Peek ().Visible)
+                {
+                    if (!isOverlapped && _topLevels.Peek () == OverlappedTop)
+                    {
+                        isOverlapped = true;
+                    }
+                    else if (isOverlapped && _topLevels.Peek () == OverlappedTop)
+                    {
+                        MoveCurrent (Top);
+
+                        break;
+                    }
+
+                    _topLevels.MovePrevious ();
+                }
+
+                Current = _topLevels.Peek ();
+            }
+        }
+    }
+
+    private static bool OverlappedChildNeedsDisplay ()
+    {
+        if (OverlappedTop is null)
+        {
+            return false;
+        }
+
+        foreach (Toplevel top in _topLevels)
+        {
+            if (top != Current && top.Visible && (top.NeedsDisplay || top.SubViewNeedsDisplay || top.LayoutNeeded))
+            {
+                OverlappedTop.SetSubViewNeedsDisplay ();
+
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    private static bool SetCurrentOverlappedAsTop ()
+    {
+        if (OverlappedTop is null && Current != Top && Current?.SuperView is null && Current?.Modal == false)
+        {
+            Top = Current;
+
+            return true;
+        }
+
+        return false;
+    }
+}
\ No newline at end of file
diff --git a/Terminal.Gui/Application/Application.Overlapped.cs b/Terminal.Gui/Application/Application.Overlapped.cs
new file mode 100644
index 000000000..58eccfa3a
--- /dev/null
+++ b/Terminal.Gui/Application/Application.Overlapped.cs
@@ -0,0 +1,7 @@
+#nullable enable
+namespace Terminal.Gui;
+
+public static partial class Application // App-level View Navigation
+{
+ 
+}
\ No newline at end of file
diff --git a/Terminal.Gui/Application/Application.Run.cs b/Terminal.Gui/Application/Application.Run.cs
index e5e51a0fb..541ad7141 100644
--- a/Terminal.Gui/Application/Application.Run.cs
+++ b/Terminal.Gui/Application/Application.Run.cs
@@ -1,3 +1,4 @@
+#nullable enable
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 
diff --git a/Terminal.Gui/Application/Application.Toplevel.cs b/Terminal.Gui/Application/Application.Toplevel.cs
index b08f9e960..d8996a383 100644
--- a/Terminal.Gui/Application/Application.Toplevel.cs
+++ b/Terminal.Gui/Application/Application.Toplevel.cs
@@ -1,10 +1,10 @@
+#nullable enable
 namespace Terminal.Gui;
 
 public static partial class Application // Toplevel handling
 {
-    /// <summary>Holds the stack of TopLevel views.</summary>
-
     // BUGBUG: Technically, this is not the full lst of TopLevels. There be dragons here, e.g. see how Toplevel.Id is used. What
+    /// <summary>Holds the stack of TopLevel views.</summary>
     // about TopLevels that are just a SubView of another View?
     internal static readonly Stack<Toplevel> _topLevels = new ();
 
@@ -12,6 +12,7 @@ public static partial class Application // Toplevel handling
     /// <value>The top.</value>
     public static Toplevel Top { get; private set; }
 
+    // TODO: Determine why this can't just return _topLevels.Peek()?
     /// <summary>
     ///     The current <see cref="Toplevel"/> object. This is updated in <see cref="Application.Begin"/> enters and leaves to
     ///     point to the current
@@ -23,6 +24,9 @@ public static partial class Application // Toplevel handling
     /// <value>The current.</value>
     public static Toplevel Current { get; private set; }
 
+    /// <summary>
+    ///     If <paramref name="topLevel"/> is not already Current and visible, finds the last Modal Toplevel in the stack and makes it Current.
+    /// </summary>
     private static void EnsureModalOrVisibleAlwaysOnTop (Toplevel topLevel)
     {
         if (!topLevel.Running
@@ -49,6 +53,12 @@ public static partial class Application // Toplevel handling
         }
     }
 
+    /// <summary>
+    ///    Finds the first Toplevel in the stack that is Visible and who's Frame contains the <paramref name="location"/>.
+    /// </summary>
+    /// <param name="start"></param>
+    /// <param name="location"></param>
+    /// <returns></returns>
     private static Toplevel FindDeepestTop (Toplevel start, in Point location)
     {
         if (!start.Frame.Contains (location))
@@ -78,6 +88,9 @@ public static partial class Application // Toplevel handling
         return start;
     }
 
+    /// <summary>
+    /// Given <paramref name="view"/>, returns the first Superview up the chain that is <see cref="Top"/>.
+    /// </summary>
     private static View FindTopFromView (View view)
     {
         View top = view?.SuperView is { } && view?.SuperView != Top
@@ -92,6 +105,11 @@ public static partial class Application // Toplevel handling
         return top;
     }
 
+    /// <summary>
+    ///    If the <see cref="Current"/> is not the <paramref name="top"/> then <paramref name="top"/> is moved to the top of the Toplevel stack and made Current.
+    /// </summary>
+    /// <param name="top"></param>
+    /// <returns></returns>
     private static bool MoveCurrent (Toplevel top)
     {
         // The Current is modal and the top is not modal Toplevel then
diff --git a/Terminal.Gui/View/ViewSubViews.cs b/Terminal.Gui/View/ViewSubViews.cs
index 99f9e119b..38863828a 100644
--- a/Terminal.Gui/View/ViewSubViews.cs
+++ b/Terminal.Gui/View/ViewSubViews.cs
@@ -627,7 +627,7 @@ public partial class View
         }
     }
 
-    /// <summary>Causes the specified view and the entire parent hierarchy to have the focused order updated.</summary>
+    /// <summary>Causes this view to be focused and entire Superview hierarchy to have the focused order updated.</summary>
     public void SetFocus ()
     {
         if (!CanBeVisible (this) || !Enabled)
@@ -651,7 +651,7 @@ public partial class View
     }
 
     /// <summary>
-    ///     Finds the first view in the hierarchy that wants to get the focus if nothing is currently focused, otherwise,
+    ///     If there is no focused subview, calls <see cref="FocusFirst"/> or <see cref="FocusLast"/> based on <see cref="FocusDirection"/>. 
     ///     does nothing.
     /// </summary>
     public void EnsureFocus ()
@@ -669,7 +669,9 @@ public partial class View
         }
     }
 
-    /// <summary>Focuses the first focusable subview if one exists.</summary>
+    /// <summary>
+    ///     Focuses the last focusable view in <see cref="View.TabIndexes"/> if one exists. If there are no views in <see cref="View.TabIndexes"/> then the focus is set to the view itself.
+    /// </summary>
     public void FocusFirst ()
     {
         if (!CanBeVisible (this))
@@ -695,7 +697,9 @@ public partial class View
         }
     }
 
-    /// <summary>Focuses the last focusable subview if one exists.</summary>
+    /// <summary>
+    ///     Focuses the last focusable view in <see cref="View.TabIndexes"/> if one exists. If there are no views in <see cref="View.TabIndexes"/> then the focus is set to the view itself.
+    /// </summary>
     public void FocusLast ()
     {
         if (!CanBeVisible (this))
@@ -725,7 +729,9 @@ public partial class View
         }
     }
 
-    /// <summary>Focuses the previous view.</summary>
+    /// <summary>
+    ///     Focuses the previous view in <see cref="View.TabIndexes"/>. If there is no previous view, the focus is set to the view itself.
+    /// </summary>
     /// <returns><see langword="true"/> if previous was focused, <see langword="false"/> otherwise.</returns>
     public bool FocusPrev ()
     {
@@ -736,7 +742,7 @@ public partial class View
 
         FocusDirection = NavigationDirection.Backward;
 
-        if (_tabIndexes is null || _tabIndexes.Count == 0)
+        if (TabIndexes is null || TabIndexes.Count == 0)
         {
             return false;
         }
@@ -750,10 +756,10 @@ public partial class View
 
         int focusedIdx = -1;
 
-        for (int i = _tabIndexes.Count; i > 0;)
+        for (int i = TabIndexes.Count; i > 0;)
         {
             i--;
-            View w = _tabIndexes [i];
+            View w = TabIndexes [i];
 
             if (w.HasFocus)
             {
@@ -791,7 +797,9 @@ public partial class View
         return false;
     }
 
-    /// <summary>Focuses the next view.</summary>
+    /// <summary>
+    ///     Focuses the previous view in <see cref="View.TabIndexes"/>. If there is no previous view, the focus is set to the view itself.
+    /// </summary>
     /// <returns><see langword="true"/> if next was focused, <see langword="false"/> otherwise.</returns>
     public bool FocusNext ()
     {
@@ -802,7 +810,7 @@ public partial class View
 
         FocusDirection = NavigationDirection.Forward;
 
-        if (_tabIndexes is null || _tabIndexes.Count == 0)
+        if (TabIndexes is null || TabIndexes.Count == 0)
         {
             return false;
         }
@@ -816,9 +824,9 @@ public partial class View
 
         int focusedIdx = -1;
 
-        for (var i = 0; i < _tabIndexes.Count; i++)
+        for (var i = 0; i < TabIndexes.Count; i++)
         {
-            View w = _tabIndexes [i];
+            View w = TabIndexes [i];
 
             if (w.HasFocus)
             {
diff --git a/Terminal.Gui/Views/Toplevel.cs b/Terminal.Gui/Views/Toplevel.cs
index e14d02509..0e7090492 100644
--- a/Terminal.Gui/Views/Toplevel.cs
+++ b/Terminal.Gui/Views/Toplevel.cs
@@ -80,7 +80,7 @@ public partial class Toplevel : View
                    );
 
         /// TODO: Overlapped: Add Command.ShowHide
-        
+
         AddCommand (
                     Command.Suspend,    // TODO: Move to Application
                     () =>
@@ -566,7 +566,7 @@ public partial class Toplevel : View
 
     #endregion
 
-    #region Focus
+    #region Navigation
 
     /// <inheritdoc/>
     public override bool OnEnter (View view) { return MostFocused?.OnEnter (view) ?? base.OnEnter (view); }
@@ -574,9 +574,14 @@ public partial class Toplevel : View
     /// <inheritdoc/>
     public override bool OnLeave (View view) { return MostFocused?.OnLeave (view) ?? base.OnLeave (view); }
 
-    private void FocusNearestView (IEnumerable<View> views, NavigationDirection direction)
+    /// <summary>
+    ///    Sets the focus to the next view in the <see cref="TabIndexes"/> list. If the last view is focused, the first view is focused.
+    /// </summary>
+    /// <param name="viewsInTabIndexes"></param>
+    /// <param name="direction"></param>
+    private void FocusNearestView (IEnumerable<View> viewsInTabIndexes, NavigationDirection direction)
     {
-        if (views is null)
+        if (viewsInTabIndexes is null)
         {
             return;
         }
@@ -585,7 +590,7 @@ public partial class Toplevel : View
         var focusProcessed = false;
         var idx = 0;
 
-        foreach (View v in views)
+        foreach (View v in viewsInTabIndexes)
         {
             if (v == this)
             {
@@ -610,15 +615,20 @@ public partial class Toplevel : View
                     return;
                 }
             }
-            else if (found && !focusProcessed && idx == views.Count () - 1)
+            else if (found && !focusProcessed && idx == viewsInTabIndexes.Count () - 1)
             {
-                views.ToList () [0].SetFocus ();
+                viewsInTabIndexes.ToList () [0].SetFocus ();
             }
 
             idx++;
         }
     }
 
+    /// <summary>
+    ///    Gets the deepest focused subview of the specified <paramref name="view"/>.
+    /// </summary>
+    /// <param name="view"></param>
+    /// <returns></returns>
     private View GetDeepestFocusedSubview (View view)
     {
         if (view is null)
@@ -637,6 +647,9 @@ public partial class Toplevel : View
         return view;
     }
 
+    /// <summary>
+    ///     Moves the focus to 
+    /// </summary>
     private void MoveNextView ()
     {
         View old = GetDeepestFocusedSubview (Focused);
diff --git a/Terminal.Gui/Views/ToplevelOverlapped.cs b/Terminal.Gui/Views/ToplevelOverlapped.cs
index 0d93ef79f..3541ea091 100644
--- a/Terminal.Gui/Views/ToplevelOverlapped.cs
+++ b/Terminal.Gui/Views/ToplevelOverlapped.cs
@@ -9,212 +9,3 @@ public partial class Toplevel
     public bool IsOverlappedContainer { get; set; }
 }
 
-public static partial class Application
-{
-    /// <summary>
-    ///     Gets the list of the Overlapped children which are not modal <see cref="Toplevel"/> from the
-    ///     <see cref="OverlappedTop"/>.
-    /// </summary>
-    public static List<Toplevel> OverlappedChildren
-    {
-        get
-        {
-            if (OverlappedTop is { })
-            {
-                List<Toplevel> _overlappedChildren = new ();
-
-                foreach (Toplevel top in _topLevels)
-                {
-                    if (top != OverlappedTop && !top.Modal)
-                    {
-                        _overlappedChildren.Add (top);
-                    }
-                }
-
-                return _overlappedChildren;
-            }
-
-            return null;
-        }
-    }
-
-    #nullable enable
-    /// <summary>
-    ///     The <see cref="Toplevel"/> object used for the application on startup which
-    ///     <see cref="Toplevel.IsOverlappedContainer"/> is true.
-    /// </summary>
-    public static Toplevel? OverlappedTop
-    {
-        get
-        {
-            if (Top is { IsOverlappedContainer: true })
-            {
-                return Top;
-            }
-
-            return null;
-        }
-    }
-    #nullable restore
-
-    /// <summary>Brings the superview of the most focused overlapped view is on front.</summary>
-    public static void BringOverlappedTopToFront ()
-    {
-        if (OverlappedTop is { })
-        {
-            return;
-        }
-
-        View top = FindTopFromView (Top?.MostFocused);
-
-        if (top is Toplevel && Top.Subviews.Count > 1 && Top.Subviews [^1] != top)
-        {
-            Top.BringSubviewToFront (top);
-        }
-    }
-
-    /// <summary>Gets the current visible Toplevel overlapped child that matches the arguments pattern.</summary>
-    /// <param name="type">The type.</param>
-    /// <param name="exclude">The strings to exclude.</param>
-    /// <returns>The matched view.</returns>
-    public static Toplevel GetTopOverlappedChild (Type type = null, string [] exclude = null)
-    {
-        if (OverlappedTop is null)
-        {
-            return null;
-        }
-
-        foreach (Toplevel top in OverlappedChildren)
-        {
-            if (type is { } && top.GetType () == type && exclude?.Contains (top.Data.ToString ()) == false)
-            {
-                return top;
-            }
-
-            if ((type is { } && top.GetType () != type) || exclude?.Contains (top.Data.ToString ()) == true)
-            {
-                continue;
-            }
-
-            return top;
-        }
-
-        return null;
-    }
-
-    /// <summary>
-    ///     Move to the next Overlapped child from the <see cref="OverlappedTop"/> and set it as the <see cref="Top"/> if
-    ///     it is not already.
-    /// </summary>
-    /// <param name="top"></param>
-    /// <returns></returns>
-    public static bool MoveToOverlappedChild (Toplevel top)
-    {
-        if (top.Visible && OverlappedTop is { } && Current?.Modal == false)
-        {
-            lock (_topLevels)
-            {
-                _topLevels.MoveTo (top, 0, new ToplevelEqualityComparer ());
-                Current = top;
-            }
-
-            return true;
-        }
-
-        return false;
-    }
-
-    /// <summary>Move to the next Overlapped child from the <see cref="OverlappedTop"/>.</summary>
-    public static void OverlappedMoveNext ()
-    {
-        if (OverlappedTop is { } && !Current.Modal)
-        {
-            lock (_topLevels)
-            {
-                _topLevels.MoveNext ();
-                var isOverlapped = false;
-
-                while (_topLevels.Peek () == OverlappedTop || !_topLevels.Peek ().Visible)
-                {
-                    if (!isOverlapped && _topLevels.Peek () == OverlappedTop)
-                    {
-                        isOverlapped = true;
-                    }
-                    else if (isOverlapped && _topLevels.Peek () == OverlappedTop)
-                    {
-                        MoveCurrent (Top);
-
-                        break;
-                    }
-
-                    _topLevels.MoveNext ();
-                }
-
-                Current = _topLevels.Peek ();
-            }
-        }
-    }
-
-    /// <summary>Move to the previous Overlapped child from the <see cref="OverlappedTop"/>.</summary>
-    public static void OverlappedMovePrevious ()
-    {
-        if (OverlappedTop is { } && !Current.Modal)
-        {
-            lock (_topLevels)
-            {
-                _topLevels.MovePrevious ();
-                var isOverlapped = false;
-
-                while (_topLevels.Peek () == OverlappedTop || !_topLevels.Peek ().Visible)
-                {
-                    if (!isOverlapped && _topLevels.Peek () == OverlappedTop)
-                    {
-                        isOverlapped = true;
-                    }
-                    else if (isOverlapped && _topLevels.Peek () == OverlappedTop)
-                    {
-                        MoveCurrent (Top);
-
-                        break;
-                    }
-
-                    _topLevels.MovePrevious ();
-                }
-
-                Current = _topLevels.Peek ();
-            }
-        }
-    }
-
-    private static bool OverlappedChildNeedsDisplay ()
-    {
-        if (OverlappedTop is null)
-        {
-            return false;
-        }
-
-        foreach (Toplevel top in _topLevels)
-        {
-            if (top != Current && top.Visible && (top.NeedsDisplay || top.SubViewNeedsDisplay || top.LayoutNeeded))
-            {
-                OverlappedTop.SetSubViewNeedsDisplay ();
-
-                return true;
-            }
-        }
-
-        return false;
-    }
-
-    private static bool SetCurrentOverlappedAsTop ()
-    {
-        if (OverlappedTop is null && Current != Top && Current?.SuperView is null && Current?.Modal == false)
-        {
-            Top = Current;
-
-            return true;
-        }
-
-        return false;
-    }
-}

From feaf5c0f6c34f0767d660fa5916580b8835e7569 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Tue, 23 Jul 2024 18:12:43 -0600
Subject: [PATCH 12/33] WIP (Very Broken) try to move keybindings out of
 Toplevel to app

---
 .../Application/Application.Initialization.cs |   2 +-
 .../Application/Application.Keyboard.cs       | 203 ++++++++++++++----
 Terminal.Gui/Input/KeyBindings.cs             |  19 +-
 Terminal.Gui/View/ViewKeyboard.cs             |   2 +-
 4 files changed, 177 insertions(+), 49 deletions(-)

diff --git a/Terminal.Gui/Application/Application.Initialization.cs b/Terminal.Gui/Application/Application.Initialization.cs
index 0434eb873..2e184b285 100644
--- a/Terminal.Gui/Application/Application.Initialization.cs
+++ b/Terminal.Gui/Application/Application.Initialization.cs
@@ -89,7 +89,7 @@ public static partial class Application // Initialization (Init/Shutdown)
         Load ();
         Apply ();
 
-        AddToplevelKeyBindings ();
+        AddApplicationKeyBindings ();
 
         // Ignore Configuration for ForceDriver if driverName is specified
         if (!string.IsNullOrEmpty (driverName))
diff --git a/Terminal.Gui/Application/Application.Keyboard.cs b/Terminal.Gui/Application/Application.Keyboard.cs
index a299a7aee..209520f47 100644
--- a/Terminal.Gui/Application/Application.Keyboard.cs
+++ b/Terminal.Gui/Application/Application.Keyboard.cs
@@ -213,61 +213,172 @@ public static partial class Application // Keyboard handling
         return false;
     }
 
-    /// <summary>
-    ///     The <see cref="KeyBindingScope.Application"/> key bindings.
-    /// </summary>
-    private static readonly Dictionary<Key, List<View?>> _keyBindings = new ();
+    /// <summary>Gets the key bindings for this view.</summary>
+    public static KeyBindings KeyBindings { get; internal set; } = new ();
 
     /// <summary>
-    /// Gets the list of <see cref="KeyBindingScope.Application"/> key bindings.
+    /// Commands for Application.
     /// </summary>
-    public static Dictionary<Key, List<View?>> GetKeyBindings () { return _keyBindings; }
+    private static Dictionary<Command, Func<CommandContext, bool?>> CommandImplementations { get; } = new ();
 
     /// <summary>
-    ///     Adds an  <see cref="KeyBindingScope.Application"/> scoped key binding.
+    ///     <para>
+    ///         Sets the function that will be invoked for a <see cref="Command"/>. 
+    ///     </para>
+    ///     <para>
+    ///         If AddCommand has already been called for <paramref name="command"/> <paramref name="f"/> will
+    ///         replace the old one.
+    ///     </para>
     /// </summary>
     /// <remarks>
-    ///     This is an internal method used by the <see cref="View"/> class to add Application key bindings.
+    /// <para>
+    ///     This version of AddCommand is for commands that do not require a <see cref="CommandContext"/>.
+    /// </para>
     /// </remarks>
-    /// <param name="key">The key being bound.</param>
-    /// <param name="view">The view that is bound to the key. If <see langword="null"/>, <see cref="Application.Current"/> will be used.</param>
-    internal static void AddKeyBinding (Key key, View? view)
+    /// <param name="command">The command.</param>
+    /// <param name="f">The function.</param>
+    private static void AddCommand (Command command, Func<bool?> f)
     {
-        if (!_keyBindings.ContainsKey (key))
-        {
-            _keyBindings [key] = [];
-        }
-
-        _keyBindings [key].Add (view);
+        CommandImplementations [command] = ctx => f ();
     }
 
-    internal static void AddToplevelKeyBindings ()
+    ///// <summary>
+    /////     The <see cref="KeyBindingScope.Application"/> key bindings.
+    ///// </summary>
+    //private static readonly Dictionary<Key, List<View?>> _keyBindings = new ();
+
+    ///// <summary>
+    ///// Gets the list of <see cref="KeyBindingScope.Application"/> key bindings.
+    ///// </summary>
+    //public static Dictionary<Key, List<View?>> GetKeyBindings () { return _keyBindings; }
+
+    ///// <summary>
+    /////     Adds an  <see cref="KeyBindingScope.Application"/> scoped key binding.
+    ///// </summary>
+    ///// <remarks>
+    /////     This is an internal method used by the <see cref="View"/> class to add Application key bindings.
+    ///// </remarks>
+    ///// <param name="key">The key being bound.</param>
+    ///// <param name="view">The view that is bound to the key. If <see langword="null"/>, <see cref="Application.Current"/> will be used.</param>
+    //internal static void AddKeyBinding (Key key, View? view)
+    //{
+    //    if (!_keyBindings.ContainsKey (key))
+    //    {
+    //        _keyBindings [key] = [];
+    //    }
+
+    //    _keyBindings [key].Add (view);
+    //}
+
+    internal static void AddApplicationKeyBindings ()
     {
-//        // Default keybindings for this view
-//        AddKeyBinding (Application.QuitKey, null);
-//        AddKeyBinding (Key.CursorRight, null);
-//        AddKeyBinding (Key.CursorDown, null);
-//        AddKeyBinding (Key.CursorLeft, null);
-//        AddKeyBinding (Key.CursorUp, null);
-//        AddKeyBinding (Key.Tab, null);
-//        AddKeyBinding (Key.Tab.WithShift, null);
-//        AddKeyBinding (Key.Tab.WithCtrl, null);
-//        AddKeyBinding (Key.Tab.WithShift.WithCtrl, null);
-//        AddKeyBinding (Key.F5, null);
-//        AddKeyBinding (Application.AlternateForwardKey, null); // Needed on Unix
-//        AddKeyBinding (Application.AlternateBackwardKey, null); // Needed on Unix
+        // Things this view knows how to do
+        AddCommand (
+                    Command.QuitToplevel,  // TODO: IRunnable: Rename to Command.Quit to make more generic.
+                    () =>
+                    {
+                        if (OverlappedTop is { })
+                        {
+                            RequestStop (Current);
+                        }
+                        else
+                        {
+                            Application.RequestStop ();
+                        }
 
-//        if (Environment.OSVersion.Platform == PlatformID.Unix)
-//        {
-//            AddKeyBinding (Key.Z.WithCtrl, null);
-//        }
+                        return true;
+                    }
+                   );
 
-//#if UNIX_KEY_BINDINGS
-//        KeyBindings.Add (Key.L.WithCtrl, Command.Refresh); // Unix
-//        KeyBindings.Add (Key.F.WithCtrl, Command.NextView); // Unix
-//        KeyBindings.Add (Key.I.WithCtrl, Command.NextView); // Unix
-//        KeyBindings.Add (Key.B.WithCtrl, Command.PreviousView); // Unix
-//#endif
+        AddCommand (
+                    Command.Suspend,
+                    () =>
+                    {
+                        Driver?.Suspend ();
+
+                        return true;
+                    }
+                   );
+
+        AddCommand (
+                    Command.NextView,    // TODO: Figure out how to move this to the View that is at the root of the view hierarchy (currently Application.Top)
+                    () =>
+                    {
+                        Current.MoveNextView ();
+
+                        return true;
+                    }
+                   );
+
+        AddCommand (
+                    Command.PreviousView,// TODO: Figure out how to move this to the View that is at the root of the view hierarchy (currently Application.Top)
+                    () =>
+                    {
+                        Current.MovePreviousView ();
+
+                        return true;
+                    }
+                   );
+
+        AddCommand (
+                    Command.NextViewOrTop,// TODO: Figure out how to move this to the View that is at the root of the view hierarchy (currently Application.Top)
+                    () =>
+                    {
+                        Current.MoveNextViewOrTop ();
+
+                        return true;
+                    }
+                   );
+
+        AddCommand (
+                    Command.PreviousViewOrTop,// TODO: Figure out how to move this to the View that is at the root of the view hierarchy (currently Application.Top)
+                    () =>
+                    {
+                        Current.MovePreviousViewOrTop ();
+
+                        return true;
+                    }
+                   );
+
+        AddCommand (
+                    Command.Refresh,
+                    () =>
+                    {
+                        Refresh (); 
+
+                        return true;
+                    }
+                   );
+
+
+        KeyBindings.Add (Application.QuitKey, KeyBindingScope.Application, Command.QuitToplevel);
+
+        KeyBindings.Add (Key.CursorRight, KeyBindingScope.Application, Command.NextView);
+        KeyBindings.Add (Key.CursorDown, KeyBindingScope.Application, Command.NextView);
+        KeyBindings.Add (Key.CursorLeft, KeyBindingScope.Application, Command.PreviousView);
+        KeyBindings.Add (Key.CursorUp, KeyBindingScope.Application, Command.PreviousView);
+
+        KeyBindings.Add (Key.Tab, KeyBindingScope.Application, Command.NextView);
+        KeyBindings.Add (Key.Tab.WithShift, KeyBindingScope.Application, Command.PreviousView);
+        KeyBindings.Add (Key.Tab.WithCtrl, KeyBindingScope.Application, Command.NextViewOrTop);
+        KeyBindings.Add (Key.Tab.WithShift.WithCtrl, KeyBindingScope.Application, Command.PreviousViewOrTop);
+
+        // TODO: Refresh Key should be configurable
+        KeyBindings.Add (Key.F5, KeyBindingScope.Application, Command.Refresh);
+        KeyBindings.Add (Application.AlternateForwardKey, KeyBindingScope.Application, Command.NextViewOrTop); // Needed on Unix
+        KeyBindings.Add (Application.AlternateBackwardKey, KeyBindingScope.Application, Command.PreviousViewOrTop); // Needed on Unix
+
+        if (Environment.OSVersion.Platform == PlatformID.Unix)
+        {
+            KeyBindings.Add (Key.Z.WithCtrl, Command.Suspend);
+        }
+
+#if UNIX_KEY_BINDINGS
+        KeyBindings.Add (Key.L.WithCtrl, Command.Refresh); // Unix
+        KeyBindings.Add (Key.F.WithCtrl, Command.NextView); // Unix
+        KeyBindings.Add (Key.I.WithCtrl, Command.NextView); // Unix
+        KeyBindings.Add (Key.B.WithCtrl, Command.PreviousView); // Unix
+#endif
     }
 
     /// <summary>
@@ -277,7 +388,15 @@ public static partial class Application // Keyboard handling
     ///     This is an internal method used by the <see cref="View"/> class to add Application key bindings.
     /// </remarks>
     /// <returns>The list of Views that have Application-scoped key bindings.</returns>
-    internal static List<View> GetViewsWithKeyBindings () { return _keyBindings.Values.SelectMany (v => v).ToList (); }
+    internal static List<KeyBinding> GetViewKeyBindings ()
+    {
+        // Get the list of views that do not have Application-scoped key bindings
+        return KeyBindings.Bindings
+                          .Where (kv => kv.Value.Scope != KeyBindingScope.Application)
+                          .Select (kv => kv.Value)
+                          .Distinct ()
+                          .ToList ();
+    }
 
     /// <summary>
     ///     Gets the list of Views that have <see cref="KeyBindingScope.Application"/> key bindings for the specified key.
diff --git a/Terminal.Gui/Input/KeyBindings.cs b/Terminal.Gui/Input/KeyBindings.cs
index a55169606..0ea164a40 100644
--- a/Terminal.Gui/Input/KeyBindings.cs
+++ b/Terminal.Gui/Input/KeyBindings.cs
@@ -11,7 +11,7 @@ public class KeyBindings
 {
     /// <summary>
     ///     Initializes a new instance. This constructor is used when the <see cref="KeyBindings"/> are not bound to a
-    ///     <see cref="View"/>, such as in unit tests.
+    ///     <see cref="View"/>. This is used for Application.KeyBindings and unit tests.
     /// </summary>
     public KeyBindings () { }
 
@@ -21,6 +21,9 @@ public class KeyBindings
     /// <summary>
     ///     The view that the <see cref="KeyBindings"/> are bound to.
     /// </summary>
+    /// <remarks>
+    ///     If <see langword="null"/>, the <see cref="KeyBindings"/> are not bound to a <see cref="View"/>. This is used for Application.KeyBindings.
+    /// </remarks>
     public View? BoundView { get; }
 
     // TODO: Add a dictionary comparer that ignores Scope
@@ -33,6 +36,11 @@ public class KeyBindings
     /// <param name="binding"></param>
     public void Add (Key key, KeyBinding binding)
     {
+        if (BoundView is { } && binding.Scope.FastHasFlags (KeyBindingScope.Application))
+        {
+            throw new ArgumentException ("Application scoped KeyBindings must be added via Application.KeyBindings.Add");
+        }
+
         if (TryGet (key, out KeyBinding _))
         {
             Bindings [key] = binding;
@@ -40,10 +48,6 @@ public class KeyBindings
         else
         {
             Bindings.Add (key, binding);
-            if (binding.Scope.HasFlag (KeyBindingScope.Application))
-            {
-                Application.AddKeyBinding (key, BoundView);
-            }
         }
     }
 
@@ -67,6 +71,11 @@ public class KeyBindings
     /// </param>
     public void Add (Key key, KeyBindingScope scope, params Command [] commands)
     {
+        if (BoundView is { } && scope.FastHasFlags (KeyBindingScope.Application))
+        {
+            throw new ArgumentException ("Application scoped KeyBindings must be added via Application.KeyBindings.Add");
+        }
+
         if (key is null || !key.IsValid)
         {
             //throw new ArgumentException ("Invalid Key", nameof (commands));
diff --git a/Terminal.Gui/View/ViewKeyboard.cs b/Terminal.Gui/View/ViewKeyboard.cs
index d103d894d..36ec6e661 100644
--- a/Terminal.Gui/View/ViewKeyboard.cs
+++ b/Terminal.Gui/View/ViewKeyboard.cs
@@ -641,7 +641,7 @@ public partial class View
     /// </returns>
     public virtual bool? OnInvokingKeyBindings (Key keyEvent, KeyBindingScope scope)
     {
-        // fire event only if there's an hotkey binding for the key
+        // fire event only if there's a hotkey binding for the key
         if (KeyBindings.TryGet (keyEvent, scope, out KeyBinding kb))
         {
             InvokingKeyBindings?.Invoke (this, keyEvent);

From c03dd320318f3a2d287dfed973c6df013871ce99 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Wed, 24 Jul 2024 12:28:30 -0600
Subject: [PATCH 13/33] Moved Toplevel keybindings out of Toplevel to
 Application. Still need to move navigation code out of Toplevel

---
 .../Application/Application.Keyboard.cs       | 145 ++--
 Terminal.Gui/Application/Application.cs       |   2 +-
 Terminal.Gui/Input/KeyBinding.cs              |  16 +
 Terminal.Gui/Input/KeyBindings.cs             | 138 +++-
 Terminal.Gui/View/ViewKeyboard.cs             |  15 +-
 Terminal.Gui/Views/DateField.cs               |  26 +-
 Terminal.Gui/Views/FileDialog.cs              |  10 +-
 Terminal.Gui/Views/Menu/Menu.cs               |   3 +
 Terminal.Gui/Views/Menu/MenuBarItem.cs        |   1 +
 Terminal.Gui/Views/MenuBarv2.cs               |   2 -
 Terminal.Gui/Views/Shortcut.cs                | 644 +++++++++---------
 Terminal.Gui/Views/Slider.cs                  |   4 +
 Terminal.Gui/Views/StatusBar.cs               |   2 -
 .../TableView/CheckBoxTableSourceWrapper.cs   |   2 +-
 Terminal.Gui/Views/TableView/TableView.cs     |   2 +-
 Terminal.Gui/Views/TextField.cs               |   5 +-
 Terminal.Gui/Views/TextValidateField.cs       |   1 -
 Terminal.Gui/Views/TextView.cs                |  18 +-
 Terminal.Gui/Views/TimeField.cs               |  26 +-
 Terminal.Gui/Views/Toplevel.cs                |  16 +-
 Terminal.Gui/Views/TreeView/TreeView.cs       |   2 +-
 UICatalog/Scenarios/KeyBindings.cs            |  37 +-
 UICatalog/Scenarios/ListColumns.cs            |   2 +-
 UICatalog/Scenarios/TableEditor.cs            |   2 +-
 UICatalog/UICatalog.cs                        |   2 +
 UnitTests/Application/ApplicationTests.cs     |   4 +-
 UnitTests/Application/KeyboardTests.cs        | 154 ++---
 UnitTests/Input/KeyBindingTests.cs            |  64 +-
 UnitTests/View/MouseTests.cs                  | 188 +----
 UnitTests/View/NavigationTests.cs             | 223 +++++-
 UnitTests/View/ViewKeyBindingTests.cs         |   5 +-
 UnitTests/Views/AllViewsTests.cs              |   8 +-
 UnitTests/Views/OverlappedTests.cs            |  94 ++-
 UnitTests/Views/TableViewTests.cs             |   8 +-
 UnitTests/Views/ToplevelTests.cs              |  32 +-
 UnitTests/Views/TreeTableSourceTests.cs       |   2 +-
 36 files changed, 1035 insertions(+), 870 deletions(-)

diff --git a/Terminal.Gui/Application/Application.Keyboard.cs b/Terminal.Gui/Application/Application.Keyboard.cs
index 209520f47..c725b13bd 100644
--- a/Terminal.Gui/Application/Application.Keyboard.cs
+++ b/Terminal.Gui/Application/Application.Keyboard.cs
@@ -1,5 +1,6 @@
 #nullable enable
 using System.Text.Json.Serialization;
+using static System.Formats.Asn1.AsnWriter;
 
 namespace Terminal.Gui;
 
@@ -19,6 +20,15 @@ public static partial class Application // Keyboard handling
             {
                 Key oldKey = _alternateForwardKey;
                 _alternateForwardKey = value;
+
+                if (_alternateForwardKey == Key.Empty)
+                {
+                    KeyBindings.Remove (_alternateForwardKey);
+                }
+                else
+                {
+                    KeyBindings.ReplaceKey (oldKey, _alternateForwardKey);
+                }
                 OnAlternateForwardKeyChanged (new (oldKey, value));
             }
         }
@@ -47,6 +57,16 @@ public static partial class Application // Keyboard handling
             {
                 Key oldKey = _alternateBackwardKey;
                 _alternateBackwardKey = value;
+
+                if (_alternateBackwardKey == Key.Empty)
+                {
+                    KeyBindings.Remove (_alternateBackwardKey);
+                }
+                else
+                {
+                    KeyBindings.ReplaceKey (oldKey, _alternateBackwardKey);
+                }
+
                 OnAlternateBackwardKeyChanged (new (oldKey, value));
             }
         }
@@ -75,6 +95,14 @@ public static partial class Application // Keyboard handling
             {
                 Key oldKey = _quitKey;
                 _quitKey = value;
+                if (_quitKey == Key.Empty)
+                {
+                    KeyBindings.Remove (_quitKey);
+                }
+                else
+                {
+                    KeyBindings.ReplaceKey (oldKey, _quitKey);
+                }
                 OnQuitKeyChanged (new (oldKey, value));
             }
         }
@@ -139,26 +167,55 @@ public static partial class Application // Keyboard handling
             }
         }
 
-        // Invoke any global (Application-scoped) KeyBindings.
+        // Invoke any Application-scoped KeyBindings.
         // The first view that handles the key will stop the loop.
-        foreach (KeyValuePair<Key, List<View?>> binding in _keyBindings.Where (b => b.Key == keyEvent.KeyCode))
+        foreach (var binding in KeyBindings.Bindings.Where (b => b.Key == keyEvent.KeyCode))
         {
-            foreach (View view in binding.Value)
+            if (binding.Value.BoundView is { })
             {
-                if (view is { }
-                    && view.KeyBindings.TryGet (binding.Key, KeyBindingScope.Focused | KeyBindingScope.HotKey | KeyBindingScope.Application, out KeyBinding kb))
-                {
-                    //bool? handled = view.InvokeCommands (kb.Commands, binding.Key, kb);
-                    bool? handled = view?.OnInvokingKeyBindings (keyEvent, kb.Scope);
+                bool? handled = binding.Value.BoundView?.InvokeCommands (binding.Value.Commands, binding.Key, binding.Value);
 
-                    if (handled != null && (bool)handled)
-                    {
-                        return true;
-                    }
+                if (handled != null && (bool)handled)
+                {
+                    return true;
                 }
             }
+            else
+            {
+                if (!KeyBindings.TryGet (keyEvent, KeyBindingScope.Application, out KeyBinding appBinding))
+                {
+                    continue;
+                }
+
+                bool? toReturn = null;
+
+                foreach (Command command in appBinding.Commands)
+                {
+                    if (!CommandImplementations.ContainsKey (command))
+                    {
+                        throw new NotSupportedException (
+                                                         @$"A KeyBinding was set up for the command {command} ({keyEvent}) but that command is not supported by Application."
+                                                        );
+                    }
+
+                    if (CommandImplementations.TryGetValue (command, out Func<CommandContext, bool?>? implementation))
+                    {
+                        var context = new CommandContext (command, keyEvent, appBinding); // Create the context here
+                        toReturn = implementation (context);
+                    }
+
+                    // if ever see a true then that's what we will return
+                    if (toReturn ?? false)
+                    {
+                        toReturn = true;
+                    }
+                }
+
+                return toReturn ?? true;
+            }
         }
 
+
         return false;
     }
 
@@ -344,7 +401,7 @@ public static partial class Application // Keyboard handling
                     Command.Refresh,
                     () =>
                     {
-                        Refresh (); 
+                        Refresh ();
 
                         return true;
                     }
@@ -370,7 +427,7 @@ public static partial class Application // Keyboard handling
 
         if (Environment.OSVersion.Platform == PlatformID.Unix)
         {
-            KeyBindings.Add (Key.Z.WithCtrl, Command.Suspend);
+            KeyBindings.Add (Key.Z.WithCtrl, KeyBindingScope.Application, Command.Suspend);
         }
 
 #if UNIX_KEY_BINDINGS
@@ -398,37 +455,16 @@ public static partial class Application // Keyboard handling
                           .ToList ();
     }
 
-    /// <summary>
-    ///     Gets the list of Views that have <see cref="KeyBindingScope.Application"/> key bindings for the specified key.
-    /// </summary>
-    /// <remarks>
-    ///     This is an internal method used by the <see cref="View"/> class to add Application key bindings.
-    /// </remarks>
-    /// <param name="key">The key to check.</param>
-    /// <param name="views">Outputs the list of views bound to <paramref name="key"/></param>
-    /// <returns><see langword="True"/> if successful.</returns>
-    internal static bool TryGetKeyBindings (Key key, out List<View> views) { return _keyBindings.TryGetValue (key, out views); }
-
-    /// <summary>
-    ///     Removes an <see cref="KeyBindingScope.Application"/> scoped key binding.
-    /// </summary>
-    /// <remarks>
-    ///     This is an internal method used by the <see cref="View"/> class to remove Application key bindings.
-    /// </remarks>
-    /// <param name="key">The key that was bound.</param>
-    /// <param name="view">The view that is bound to the key.</param>
-    internal static void RemoveKeyBinding (Key key, View view)
-    {
-        if (_keyBindings.TryGetValue (key, out List<View> views))
-        {
-            views.Remove (view);
-
-            if (views.Count == 0)
-            {
-                _keyBindings.Remove (key);
-            }
-        }
-    }
+    ///// <summary>
+    /////     Gets the list of Views that have <see cref="KeyBindingScope.Application"/> key bindings for the specified key.
+    ///// </summary>
+    ///// <remarks>
+    /////     This is an internal method used by the <see cref="View"/> class to add Application key bindings.
+    ///// </remarks>
+    ///// <param name="key">The key to check.</param>
+    ///// <param name="views">Outputs the list of views bound to <paramref name="key"/></param>
+    ///// <returns><see langword="True"/> if successful.</returns>
+    //internal static bool TryGetKeyBindings (Key key, out List<View> views) { return _keyBindings.TryGetValue (key, out views); }
 
     /// <summary>
     ///     Removes all <see cref="KeyBindingScope.Application"/> scoped key bindings for the specified view.
@@ -437,19 +473,12 @@ public static partial class Application // Keyboard handling
     ///     This is an internal method used by the <see cref="View"/> class to remove Application key bindings.
     /// </remarks>
     /// <param name="view">The view that is bound to the key.</param>
-    internal static void ClearKeyBindings (View view)
+    internal static void RemoveKeyBindings (View view)
     {
-        foreach (Key key in _keyBindings.Keys)
-        {
-            _keyBindings [key].Remove (view);
-        }
+        var list = KeyBindings.Bindings
+                          .Where (kv => kv.Value.Scope != KeyBindingScope.Application)
+                          .Select (kv => kv.Value)
+                          .Distinct ()
+                          .ToList ();
     }
-
-    /// <summary>
-    ///     Removes all <see cref="KeyBindingScope.Application"/> scoped key bindings for the specified view.
-    /// </summary>
-    /// <remarks>
-    ///     This is an internal method used by the <see cref="View"/> class to remove Application key bindings.
-    /// </remarks>
-    internal static void ClearKeyBindings () { _keyBindings.Clear (); }
 }
diff --git a/Terminal.Gui/Application/Application.cs b/Terminal.Gui/Application/Application.cs
index 3b4c9d9f7..76c05922b 100644
--- a/Terminal.Gui/Application/Application.cs
+++ b/Terminal.Gui/Application/Application.cs
@@ -126,7 +126,7 @@ public static partial class Application
         KeyDown = null;
         KeyUp = null;
         SizeChanging = null;
-        ClearKeyBindings ();
+        KeyBindings.Clear ();
 
         Colors.Reset ();
 
diff --git a/Terminal.Gui/Input/KeyBinding.cs b/Terminal.Gui/Input/KeyBinding.cs
index baac07384..8b5a4201d 100644
--- a/Terminal.Gui/Input/KeyBinding.cs
+++ b/Terminal.Gui/Input/KeyBinding.cs
@@ -21,12 +21,28 @@ public record struct KeyBinding
         Context = context;
     }
 
+    /// <summary>Initializes a new instance.</summary>
+    /// <param name="commands">The commands this key binding will invoke.</param>
+    /// <param name="scope">The scope of the <see cref="Commands"/>.</param>
+    /// <param name="boundView">The view the key binding is bound to.</param>
+    /// <param name="context">Arbitrary context that can be associated with this key binding.</param>
+    public KeyBinding (Command [] commands, KeyBindingScope scope, View? boundView, object? context = null)
+    {
+        Commands = commands;
+        Scope = scope;
+        BoundView = boundView;
+        Context = context;
+    }
+
     /// <summary>The commands this key binding will invoke.</summary>
     public Command [] Commands { get; set; }
 
     /// <summary>The scope of the <see cref="Commands"/>.</summary>
     public KeyBindingScope Scope { get; set; }
 
+    /// <summary>The view the key binding is bound to.</summary>
+    public View? BoundView { get; set; }
+
     /// <summary>
     ///     Arbitrary context that can be associated with this key binding.
     /// </summary>
diff --git a/Terminal.Gui/Input/KeyBindings.cs b/Terminal.Gui/Input/KeyBindings.cs
index 0ea164a40..8ca45568e 100644
--- a/Terminal.Gui/Input/KeyBindings.cs
+++ b/Terminal.Gui/Input/KeyBindings.cs
@@ -1,6 +1,7 @@
 #nullable enable
 
 using System.Diagnostics;
+using Microsoft.CodeAnalysis;
 
 namespace Terminal.Gui;
 
@@ -34,7 +35,8 @@ public class KeyBindings
     /// <summary>Adds a <see cref="KeyBinding"/> to the collection.</summary>
     /// <param name="key"></param>
     /// <param name="binding"></param>
-    public void Add (Key key, KeyBinding binding)
+    /// <param name="boundViewForAppScope">Optional View for <see cref="KeyBindingScope.Application"/> bindings.</param>
+    public void Add (Key key, KeyBinding binding, View? boundViewForAppScope = null)
     {
         if (BoundView is { } && binding.Scope.FastHasFlags (KeyBindingScope.Application))
         {
@@ -43,10 +45,19 @@ public class KeyBindings
 
         if (TryGet (key, out KeyBinding _))
         {
-            Bindings [key] = binding;
+            throw new InvalidOperationException(@$"A key binding for {key} exists ({binding}).");
+            //Bindings [key] = binding;
         }
         else
         {
+            if (BoundView is { })
+            {
+                binding.BoundView = BoundView;
+            }
+            else
+            {
+                binding.BoundView = boundViewForAppScope;
+            }
             Bindings.Add (key, binding);
         }
     }
@@ -64,12 +75,13 @@ public class KeyBindings
     /// </remarks>
     /// <param name="key">The key to check.</param>
     /// <param name="scope">The scope for the command.</param>
+    /// <param name="boundViewForAppScope">Optional View for <see cref="KeyBindingScope.Application"/> bindings.</param>
     /// <param name="commands">
     ///     The command to invoked on the <see cref="View"/> when <paramref name="key"/> is pressed. When
     ///     multiple commands are provided,they will be applied in sequence. The bound <paramref name="key"/> strike will be
     ///     consumed if any took effect.
     /// </param>
-    public void Add (Key key, KeyBindingScope scope, params Command [] commands)
+    public void Add (Key key, KeyBindingScope scope, View? boundViewForAppScope = null, params Command [] commands)
     {
         if (BoundView is { } && scope.FastHasFlags (KeyBindingScope.Application))
         {
@@ -87,13 +99,43 @@ public class KeyBindings
             throw new ArgumentException (@"At least one command must be specified", nameof (commands));
         }
 
-        if (TryGet (key, out KeyBinding _))
+        if (TryGet (key, out KeyBinding binding))
         {
-            Bindings [key] = new (commands, scope);
+            throw new InvalidOperationException (@$"A key binding for {key} exists ({binding}).");
+            //Bindings [key] = new (commands, scope, BoundView);
         }
         else
         {
-            Add (key, new KeyBinding (commands, scope));
+            Add (key, new KeyBinding (commands, scope, BoundView), boundViewForAppScope);
+        }
+    }
+
+    public void Add (Key key, KeyBindingScope scope,  params Command [] commands)
+    {
+        if (BoundView is { } && scope.FastHasFlags (KeyBindingScope.Application))
+        {
+            throw new ArgumentException ("Application scoped KeyBindings must be added via Application.KeyBindings.Add");
+        }
+
+        if (key is null || !key.IsValid)
+        {
+            //throw new ArgumentException ("Invalid Key", nameof (commands));
+            return;
+        }
+
+        if (commands.Length == 0)
+        {
+            throw new ArgumentException (@"At least one command must be specified", nameof (commands));
+        }
+
+        if (TryGet (key, out KeyBinding binding))
+        {
+            throw new InvalidOperationException (@$"A key binding for {key} exists ({binding}).");
+            //Bindings [key] = new (commands, scope, BoundView);
+        }
+        else
+        {
+            Add (key, new KeyBinding (commands, scope, BoundView), null);
         }
     }
 
@@ -103,8 +145,42 @@ public class KeyBindings
     ///         View - see <see cref="View.GetSupportedCommands"/>).
     ///     </para>
     ///     <para>
-    ///         This is a helper function for <see cref="Add(Key,KeyBindingScope,Terminal.Gui.Command[])"/> for
-    ///         <see cref="KeyBindingScope.Focused"/> scoped commands.
+    ///         This is a helper function for <see cref="Add(Key,KeyBinding,View?)"/>. If used for a View (<see cref="BoundView"/> is set), the scope will be set to <see cref="KeyBindingScope.Focused"/>.
+    ///         Otherwise, it will be set to <see cref="KeyBindingScope.Application"/>.
+    ///     </para>
+    ///     <para>
+    ///         If the key is already bound to a different array of <see cref="Command"/>s it will be rebound
+    ///         <paramref name="commands"/>.
+    ///     </para>
+    /// </summary>
+    /// <remarks>
+    ///     Commands are only ever applied to the current <see cref="View"/> (i.e. this feature cannot be used to switch
+    ///     focus to another view and perform multiple commands there).
+    /// </remarks>
+    /// <param name="key">The key to check.</param>
+    /// <param name="boundViewForAppScope">Optional View for <see cref="KeyBindingScope.Application"/> bindings.</param>
+    /// <param name="commands">
+    ///     The command to invoked on the <see cref="View"/> when <paramref name="key"/> is pressed. When
+    ///     multiple commands are provided,they will be applied in sequence. The bound <paramref name="key"/> strike will be
+    ///     consumed if any took effect.
+    /// </param>
+    public void Add (Key key, View? boundViewForAppScope = null, params Command [] commands)
+    {
+        if (BoundView is null && boundViewForAppScope is null)
+        {
+            throw new ArgumentException (@"Application scoped KeyBindings must provide a bound view to Add.", nameof(boundViewForAppScope));
+        }
+        Add (key, BoundView is { } ? KeyBindingScope.Focused : KeyBindingScope.Application, boundViewForAppScope, commands);
+    }
+
+    /// <summary>
+    ///     <para>
+    ///         Adds a new key combination that will trigger the commands in <paramref name="commands"/> (if supported by the
+    ///         View - see <see cref="View.GetSupportedCommands"/>).
+    ///     </para>
+    ///     <para>
+    ///         This is a helper function for <see cref="Add(Key,KeyBinding,View?)"/>. If used for a View (<see cref="BoundView"/> is set), the scope will be set to <see cref="KeyBindingScope.Focused"/>.
+    ///         Otherwise, it will be set to <see cref="KeyBindingScope.Application"/>.
     ///     </para>
     ///     <para>
     ///         If the key is already bound to a different array of <see cref="Command"/>s it will be rebound
@@ -123,14 +199,16 @@ public class KeyBindings
     /// </param>
     public void Add (Key key, params Command [] commands)
     {
-        Add (key, KeyBindingScope.Focused, commands);
+        if (BoundView is null)
+        {
+            throw new ArgumentException (@"Application scoped KeyBindings must provide a boundViewForAppScope to Add.");
+        }
+        Add (key, BoundView is { } ? KeyBindingScope.Focused : KeyBindingScope.Application, null, commands);
     }
 
     /// <summary>Removes all <see cref="KeyBinding"/> objects from the collection.</summary>
     public void Clear ()
     {
-        Application.ClearKeyBindings (BoundView);
-
         Bindings.Clear ();
     }
 
@@ -201,17 +279,23 @@ public class KeyBindings
 
     /// <summary>Removes a <see cref="KeyBinding"/> from the collection.</summary>
     /// <param name="key"></param>
-    public void Remove (Key key)
+    /// <param name="boundViewForAppScope">Optional View for <see cref="KeyBindingScope.Application"/> bindings.</param>
+    public void Remove (Key key, View? boundViewForAppScope = null)
     {
+
+        if (!TryGet (key, out KeyBinding binding))
+        {
+            return;
+        }
+
         Bindings.Remove (key);
-        Application.RemoveKeyBinding (key, BoundView);
     }
 
     /// <summary>Replaces a key combination already bound to a set of <see cref="Command"/>s.</summary>
     /// <remarks></remarks>
     /// <param name="oldKey">The key to be replaced.</param>
     /// <param name="newKey">The new key to be used.</param>
-    public void Replace (Key oldKey, Key newKey)
+    public void ReplaceKey (Key oldKey, Key newKey)
     {
         if (!TryGet (oldKey, out KeyBinding _))
         {
@@ -223,6 +307,26 @@ public class KeyBindings
         Add (newKey, value);
     }
 
+    /// <summary>Replaces the commands already bound to a key.</summary>
+    /// <remarks>
+    ///     <para>
+    ///         If the key is not already bound, it will be added.
+    ///     </para>
+    /// </remarks>
+    /// <param name="key">The key bound to the command to be replaced.</param>
+    /// <param name="commands">The set of commands to replace the old ones with.</param>
+    public void ReplaceCommands (Key key, params Command [] commands)
+    {
+        if (TryGet (key, out KeyBinding binding))
+        {
+            binding.Commands = commands;
+        }
+        else
+        {
+            Add (key, commands);
+        }
+    }
+
     /// <summary>Gets the commands bound with the specified Key.</summary>
     /// <remarks></remarks>
     /// <param name="key">The key to check.</param>
@@ -233,13 +337,12 @@ public class KeyBindings
     /// <returns><see langword="true"/> if the Key is bound; otherwise <see langword="false"/>.</returns>
     public bool TryGet (Key key, out KeyBinding binding)
     {
+        binding = new (Array.Empty<Command> (), KeyBindingScope.Disabled, null);
         if (key.IsValid)
         {
             return Bindings.TryGetValue (key, out binding);
         }
 
-        binding = new (Array.Empty<Command> (), KeyBindingScope.Focused);
-
         return false;
     }
 
@@ -254,6 +357,7 @@ public class KeyBindings
     /// <returns><see langword="true"/> if the Key is bound; otherwise <see langword="false"/>.</returns>
     public bool TryGet (Key key, KeyBindingScope scope, out KeyBinding binding)
     {
+        binding = new (Array.Empty<Command> (), KeyBindingScope.Disabled, null);
         if (key.IsValid && Bindings.TryGetValue (key, out binding))
         {
             if (scope.HasFlag (binding.Scope))
@@ -262,8 +366,6 @@ public class KeyBindings
             }
         }
 
-        binding = new (Array.Empty<Command> (), KeyBindingScope.Focused);
-
         return false;
     }
 }
diff --git a/Terminal.Gui/View/ViewKeyboard.cs b/Terminal.Gui/View/ViewKeyboard.cs
index 36ec6e661..7a905f129 100644
--- a/Terminal.Gui/View/ViewKeyboard.cs
+++ b/Terminal.Gui/View/ViewKeyboard.cs
@@ -27,7 +27,7 @@ public partial class View
     private void DisposeKeyboard ()
     {
         TitleTextFormatter.HotKeyChanged -= TitleTextFormatter_HotKeyChanged;
-        KeyBindings.Clear ();
+        Application.RemoveKeyBindings (this);
     }
 
     #region HotKey Support
@@ -197,13 +197,17 @@ public partial class View
         {
             KeyBinding keyBinding = new ([Command.HotKey], KeyBindingScope.HotKey, context);
             // Add the base and Alt key
+            KeyBindings.Remove (newKey);
             KeyBindings.Add (newKey, keyBinding);
+            KeyBindings.Remove (newKey.WithAlt);
             KeyBindings.Add (newKey.WithAlt, keyBinding);
 
             // If the Key is A..Z, add ShiftMask and AltMask | ShiftMask
             if (newKey.IsKeyCodeAtoZ)
             {
+                KeyBindings.Remove (newKey.WithShift);
                 KeyBindings.Add (newKey.WithShift, keyBinding);
+                KeyBindings.Remove (newKey.WithShift.WithAlt);
                 KeyBindings.Add (newKey.WithShift.WithAlt, keyBinding);
             }
         }
@@ -800,11 +804,12 @@ public partial class View
 #if DEBUG
 
         // TODO: Determine if App scope bindings should be fired first or last (currently last).
-        if (Application.TryGetKeyBindings (key, out List<View> views))
+        if (Application.KeyBindings.TryGet (key, KeyBindingScope.Focused | KeyBindingScope.HotKey, out KeyBinding b))
         {
-            var boundView = views [0];
-            var commandBinding = boundView.KeyBindings.Get (key);
-            Debug.WriteLine ($"WARNING: InvokeKeyBindings ({key}) - An Application scope binding exists for this key. The registered view will not invoke Command.{commandBinding.Commands [0]}: {boundView}.");
+            //var boundView = views [0];
+            //var commandBinding = boundView.KeyBindings.Get (key);
+            Debug.WriteLine (
+                             $"WARNING: InvokeKeyBindings ({key}) - An Application scope binding exists for this key. The registered view will not invoke Command.");//{commandBinding.Commands [0]}: {boundView}.");
         }
 
         // TODO: This is a "prototype" debug check. It may be too annoying vs. useful.
diff --git a/Terminal.Gui/Views/DateField.cs b/Terminal.Gui/Views/DateField.cs
index 9627b2558..0bb3d9ad2 100644
--- a/Terminal.Gui/Views/DateField.cs
+++ b/Terminal.Gui/Views/DateField.cs
@@ -400,26 +400,26 @@ public class DateField : TextField
         AddCommand (Command.RightEnd, () => MoveEnd ());
         AddCommand (Command.Right, () => MoveRight ());
 
-        // Default keybindings for this view
-        KeyBindings.Add (Key.Delete, Command.DeleteCharRight);
-        KeyBindings.Add (Key.D.WithCtrl, Command.DeleteCharRight);
+        // Replace the commands defined in TextField
+        KeyBindings.ReplaceCommands (Key.Delete, Command.DeleteCharRight);
+        KeyBindings.ReplaceCommands (Key.D.WithCtrl, Command.DeleteCharRight);
 
-        KeyBindings.Add (Key.Backspace, Command.DeleteCharLeft);
+        KeyBindings.ReplaceCommands (Key.Backspace, Command.DeleteCharLeft);
 
-        KeyBindings.Add (Key.Home, Command.LeftHome);
-        KeyBindings.Add (Key.A.WithCtrl, Command.LeftHome);
+        KeyBindings.ReplaceCommands (Key.Home, Command.LeftHome);
+        KeyBindings.ReplaceCommands (Key.A.WithCtrl, Command.LeftHome);
 
-        KeyBindings.Add (Key.CursorLeft, Command.Left);
-        KeyBindings.Add (Key.B.WithCtrl, Command.Left);
+        KeyBindings.ReplaceCommands (Key.CursorLeft, Command.Left);
+        KeyBindings.ReplaceCommands (Key.B.WithCtrl, Command.Left);
 
-        KeyBindings.Add (Key.End, Command.RightEnd);
-        KeyBindings.Add (Key.E.WithCtrl, Command.RightEnd);
+        KeyBindings.ReplaceCommands (Key.End, Command.RightEnd);
+        KeyBindings.ReplaceCommands (Key.E.WithCtrl, Command.RightEnd);
 
-        KeyBindings.Add (Key.CursorRight, Command.Right);
-        KeyBindings.Add (Key.F.WithCtrl, Command.Right);
+        KeyBindings.ReplaceCommands (Key.CursorRight, Command.Right);
+        KeyBindings.ReplaceCommands (Key.F.WithCtrl, Command.Right);
 
 #if UNIX_KEY_BINDINGS
-        KeyBindings.Add (Key.D.WithAlt, Command.DeleteCharLeft);
+        KeyBindings.ReplaceCommands (Key.D.WithAlt, Command.DeleteCharLeft);
 #endif
 
     }
diff --git a/Terminal.Gui/Views/FileDialog.cs b/Terminal.Gui/Views/FileDialog.cs
index d167f87e3..4aa7b88e8 100644
--- a/Terminal.Gui/Views/FileDialog.cs
+++ b/Terminal.Gui/Views/FileDialog.cs
@@ -134,7 +134,7 @@ public class FileDialog : Dialog
             FullRowSelect = true,
             CollectionNavigator = new FileDialogCollectionNavigator (this)
         };
-        _tableView.KeyBindings.Add (Key.Space, Command.Select);
+        _tableView.KeyBindings.ReplaceCommands (Key.Space, Command.Select);
         _tableView.MouseClick += OnTableViewMouseClick;
         _tableView.Style.InvertSelectedCellFirstCharacter = true;
         Style.TableStyle = _tableView.Style;
@@ -254,10 +254,10 @@ public class FileDialog : Dialog
         _tableView.KeyUp += (s, k) => k.Handled = TableView_KeyUp (k);
         _tableView.SelectedCellChanged += TableView_SelectedCellChanged;
 
-        _tableView.KeyBindings.Add (Key.Home, Command.TopHome);
-        _tableView.KeyBindings.Add (Key.End, Command.BottomEnd);
-        _tableView.KeyBindings.Add (Key.Home.WithShift, Command.TopHomeExtend);
-        _tableView.KeyBindings.Add (Key.End.WithShift, Command.BottomEndExtend);
+        _tableView.KeyBindings.ReplaceCommands (Key.Home, Command.TopHome);
+        _tableView.KeyBindings.ReplaceCommands (Key.End, Command.BottomEnd);
+        _tableView.KeyBindings.ReplaceCommands (Key.Home.WithShift, Command.TopHomeExtend);
+        _tableView.KeyBindings.ReplaceCommands (Key.End.WithShift, Command.BottomEndExtend);
 
         _treeView.KeyDown += (s, k) =>
                              {
diff --git a/Terminal.Gui/Views/Menu/Menu.cs b/Terminal.Gui/Views/Menu/Menu.cs
index 34e8dab30..3e4923019 100644
--- a/Terminal.Gui/Views/Menu/Menu.cs
+++ b/Terminal.Gui/Views/Menu/Menu.cs
@@ -192,13 +192,16 @@ internal sealed class Menu : View
 
             if ((KeyCode)menuItem.HotKey.Value != KeyCode.Null)
             {
+                KeyBindings.Remove ((KeyCode)menuItem.HotKey.Value);
                 KeyBindings.Add ((KeyCode)menuItem.HotKey.Value, keyBinding);
+                KeyBindings.Remove ((KeyCode)menuItem.HotKey.Value | KeyCode.AltMask);
                 KeyBindings.Add ((KeyCode)menuItem.HotKey.Value | KeyCode.AltMask, keyBinding);
             }
 
             if (menuItem.Shortcut != KeyCode.Null)
             {
                 keyBinding = new ([Command.Select], KeyBindingScope.HotKey, menuItem);
+                KeyBindings.Remove (menuItem.Shortcut);
                 KeyBindings.Add (menuItem.Shortcut, keyBinding);
             }
 
diff --git a/Terminal.Gui/Views/Menu/MenuBarItem.cs b/Terminal.Gui/Views/Menu/MenuBarItem.cs
index ea5c35f15..81e755737 100644
--- a/Terminal.Gui/Views/Menu/MenuBarItem.cs
+++ b/Terminal.Gui/Views/Menu/MenuBarItem.cs
@@ -103,6 +103,7 @@ public class MenuBarItem : MenuItem
             if (menuItem.Shortcut != KeyCode.Null)
             {
                 KeyBinding keyBinding = new ([Command.Select], KeyBindingScope.HotKey, menuItem);
+                menuBar.KeyBindings.Remove (menuItem.Shortcut);
                 menuBar.KeyBindings.Add (menuItem.Shortcut, keyBinding);
             }
 
diff --git a/Terminal.Gui/Views/MenuBarv2.cs b/Terminal.Gui/Views/MenuBarv2.cs
index 12278a24c..d4c598dfe 100644
--- a/Terminal.Gui/Views/MenuBarv2.cs
+++ b/Terminal.Gui/Views/MenuBarv2.cs
@@ -43,8 +43,6 @@ public class MenuBarv2 : Bar
 
         if (view is Shortcut shortcut)
         {
-            shortcut.KeyBindingScope = KeyBindingScope.Application;
-
             // TODO: not happy about using AlignmentModes for this. Too implied.
             // TODO: instead, add a property (a style enum?) to Shortcut to control this
             //shortcut.AlignmentModes = AlignmentModes.EndToStart;
diff --git a/Terminal.Gui/Views/Shortcut.cs b/Terminal.Gui/Views/Shortcut.cs
index 7ddbe7c5a..a26a9684d 100644
--- a/Terminal.Gui/Views/Shortcut.cs
+++ b/Terminal.Gui/Views/Shortcut.cs
@@ -440,353 +440,361 @@ public class Shortcut : View
     }
 
     private void SetCommandViewDefaultLayout ()
-{
-    CommandView.Margin.Thickness = GetMarginThickness ();
-    CommandView.X = Pos.Align (Alignment.End, AlignmentModes);
-    CommandView.Y = 0; //Pos.Center ();
-}
-
-private void Shortcut_TitleChanged (object sender, EventArgs<string> e)
-{
-    // If the Title changes, update the CommandView text.
-    // This is a helper to make it easier to set the CommandView text.
-    // CommandView is public and replaceable, but this is a convenience.
-    _commandView.Text = Title;
-}
-
-#endregion Command
-
-#region Help
-
-/// <summary>
-///     The subview that displays the help text for the command. Internal for unit testing.
-/// </summary>
-internal View HelpView { get; } = new ();
-
-private void SetHelpViewDefaultLayout ()
-{
-    HelpView.Margin.Thickness = GetMarginThickness ();
-    HelpView.X = Pos.Align (Alignment.End, AlignmentModes);
-    HelpView.Y = 0; //Pos.Center ();
-    HelpView.Width = Dim.Auto (DimAutoStyle.Text);
-    HelpView.Height = CommandView?.Visible == true ? Dim.Height (CommandView) : 1;
-
-    HelpView.Visible = true;
-    HelpView.VerticalTextAlignment = Alignment.Center;
-}
-
-/// <summary>
-///     Gets or sets the help text displayed in the middle of the Shortcut. Identical in function to <see cref="HelpText"/>
-///     .
-/// </summary>
-public override string Text
-{
-    get => HelpView?.Text;
-    set
     {
-        if (HelpView != null)
+        CommandView.Margin.Thickness = GetMarginThickness ();
+        CommandView.X = Pos.Align (Alignment.End, AlignmentModes);
+        CommandView.Y = 0; //Pos.Center ();
+    }
+
+    private void Shortcut_TitleChanged (object sender, EventArgs<string> e)
+    {
+        // If the Title changes, update the CommandView text.
+        // This is a helper to make it easier to set the CommandView text.
+        // CommandView is public and replaceable, but this is a convenience.
+        _commandView.Text = Title;
+    }
+
+    #endregion Command
+
+    #region Help
+
+    /// <summary>
+    ///     The subview that displays the help text for the command. Internal for unit testing.
+    /// </summary>
+    internal View HelpView { get; } = new ();
+
+    private void SetHelpViewDefaultLayout ()
+    {
+        HelpView.Margin.Thickness = GetMarginThickness ();
+        HelpView.X = Pos.Align (Alignment.End, AlignmentModes);
+        HelpView.Y = 0; //Pos.Center ();
+        HelpView.Width = Dim.Auto (DimAutoStyle.Text);
+        HelpView.Height = CommandView?.Visible == true ? Dim.Height (CommandView) : 1;
+
+        HelpView.Visible = true;
+        HelpView.VerticalTextAlignment = Alignment.Center;
+    }
+
+    /// <summary>
+    ///     Gets or sets the help text displayed in the middle of the Shortcut. Identical in function to <see cref="HelpText"/>
+    ///     .
+    /// </summary>
+    public override string Text
+    {
+        get => HelpView?.Text;
+        set
         {
-            HelpView.Text = value;
-            ShowHide ();
-        }
-    }
-}
-
-/// <summary>
-///     Gets or sets the help text displayed in the middle of the Shortcut.
-/// </summary>
-public string HelpText
-{
-    get => HelpView?.Text;
-    set
-    {
-        if (HelpView != null)
-        {
-            HelpView.Text = value;
-            ShowHide ();
-        }
-    }
-}
-
-#endregion Help
-
-#region Key
-
-private Key _key = Key.Empty;
-
-/// <summary>
-///     Gets or sets the <see cref="Key"/> that will be bound to the <see cref="Command.Accept"/> command.
-/// </summary>
-public Key Key
-{
-    get => _key;
-    set
-    {
-        if (value == null)
-        {
-            throw new ArgumentNullException ();
-        }
-
-        _key = value;
-
-        UpdateKeyBinding ();
-
-        KeyView.Text = Key == Key.Empty ? string.Empty : $"{Key}";
-        ShowHide ();
-    }
-}
-
-private KeyBindingScope _keyBindingScope = KeyBindingScope.HotKey;
-
-/// <summary>
-///     Gets or sets the scope for the key binding for how <see cref="Key"/> is bound to <see cref="Command"/>.
-/// </summary>
-public KeyBindingScope KeyBindingScope
-{
-    get => _keyBindingScope;
-    set
-    {
-        _keyBindingScope = value;
-
-        UpdateKeyBinding ();
-    }
-}
-
-/// <summary>
-///     Gets the subview that displays the key. Internal for unit testing.
-/// </summary>
-
-internal View KeyView { get; } = new ();
-
-private int _minimumKeyTextSize;
-
-/// <summary>
-/// Gets or sets the minimum size of the key text. Useful for aligning the key text with other <see cref="Shortcut"/>s.
-/// </summary>
-public int MinimumKeyTextSize
-{
-    get => _minimumKeyTextSize;
-    set
-    {
-        if (value == _minimumKeyTextSize)
-        {
-            //return;
-        }
-
-        _minimumKeyTextSize = value;
-        SetKeyViewDefaultLayout ();
-        CommandView.SetNeedsLayout ();
-        HelpView.SetNeedsLayout ();
-        KeyView.SetNeedsLayout ();
-        SetSubViewNeedsDisplay ();
-    }
-}
-
-private int GetMinimumKeyViewSize () { return MinimumKeyTextSize; }
-
-private void SetKeyViewDefaultLayout ()
-{
-    KeyView.Margin.Thickness = GetMarginThickness ();
-    KeyView.X = Pos.Align (Alignment.End, AlignmentModes);
-    KeyView.Y = 0; //Pos.Center ();
-    KeyView.Width = Dim.Auto (DimAutoStyle.Text, Dim.Func (GetMinimumKeyViewSize));
-    KeyView.Height = CommandView?.Visible == true ? Dim.Height (CommandView) : 1;
-
-    KeyView.Visible = true;
-
-    // Right align the text in the keyview
-    KeyView.TextAlignment = Alignment.End;
-    KeyView.VerticalTextAlignment = Alignment.Center;
-    KeyView.KeyBindings.Clear ();
-}
-
-private void UpdateKeyBinding ()
-{
-    if (Key != null)
-    {
-        // Disable the command view key bindings
-        CommandView.KeyBindings.Remove (Key);
-        CommandView.KeyBindings.Remove (CommandView.HotKey);
-        KeyBindings.Remove (Key);
-        KeyBindings.Add (Key, KeyBindingScope | KeyBindingScope.HotKey, Command.Accept);
-        //KeyBindings.Add (Key, KeyBindingScope.HotKey, Command.Accept);
-    }
-}
-
-#endregion Key
-
-#region Accept Handling
-
-/// <summary>
-///     Called when the <see cref="Command.Accept"/> command is received. This
-///     occurs
-///     - if the user clicks anywhere on the shortcut with the mouse
-///     - if the user presses Key
-///     - if the user presses the HotKey specified by CommandView
-///     - if HasFocus and the user presses Space or Enter (or any other key bound to Command.Accept).
-/// </summary>
-protected bool? OnAccept (CommandContext ctx)
-{
-    var cancel = false;
-
-    switch (ctx.KeyBinding?.Scope)
-    {
-        case KeyBindingScope.Application:
-            cancel = base.OnAccept () == true;
-
-            break;
-
-        case KeyBindingScope.Focused:
-            base.OnAccept ();
-
-            // cancel if we're focused
-            cancel = true;
-
-            break;
-
-        case KeyBindingScope.HotKey:
-            cancel = base.OnAccept () == true;
-
-            if (CanFocus)
+            if (HelpView != null)
             {
-                SetFocus ();
-                cancel = true;
+                HelpView.Text = value;
+                ShowHide ();
+            }
+        }
+    }
+
+    /// <summary>
+    ///     Gets or sets the help text displayed in the middle of the Shortcut.
+    /// </summary>
+    public string HelpText
+    {
+        get => HelpView?.Text;
+        set
+        {
+            if (HelpView != null)
+            {
+                HelpView.Text = value;
+                ShowHide ();
+            }
+        }
+    }
+
+    #endregion Help
+
+    #region Key
+
+    private Key _key = Key.Empty;
+
+    /// <summary>
+    ///     Gets or sets the <see cref="Key"/> that will be bound to the <see cref="Command.Accept"/> command.
+    /// </summary>
+    public Key Key
+    {
+        get => _key;
+        set
+        {
+            if (value == null)
+            {
+                throw new ArgumentNullException ();
             }
 
-            break;
+            _key = value;
 
-        default:
-            // Mouse
-            cancel = base.OnAccept () == true;
+            UpdateKeyBinding ();
 
-            break;
+            KeyView.Text = Key == Key.Empty ? string.Empty : $"{Key}";
+            ShowHide ();
+        }
     }
 
-    CommandView.InvokeCommand (Command.Accept, ctx.Key, ctx.KeyBinding);
+    private KeyBindingScope _keyBindingScope = KeyBindingScope.HotKey;
 
-    if (Action is { })
+    /// <summary>
+    ///     Gets or sets the scope for the key binding for how <see cref="Key"/> is bound to <see cref="Command"/>.
+    /// </summary>
+    public KeyBindingScope KeyBindingScope
     {
-        Action.Invoke ();
-        // Assume if there's a subscriber to Action, it's handled.
-        cancel = true;
+        get => _keyBindingScope;
+        set
+        {
+            _keyBindingScope = value;
+
+            UpdateKeyBinding ();
+        }
     }
 
-    return cancel;
-}
+    /// <summary>
+    ///     Gets the subview that displays the key. Internal for unit testing.
+    /// </summary>
 
-/// <summary>
-///     Gets or sets the action to be invoked when the shortcut key is pressed or the shortcut is clicked on with the
-///     mouse.
-/// </summary>
-/// <remarks>
-///     Note, the <see cref="View.Accept"/> event is fired first, and if cancelled, the event will not be invoked.
-/// </remarks>
-[CanBeNull]
-public Action Action { get; set; }
+    internal View KeyView { get; } = new ();
 
-#endregion Accept Handling
+    private int _minimumKeyTextSize;
 
-private bool? OnSelect (CommandContext ctx)
-{
-    if (CommandView.GetSupportedCommands ().Contains (Command.Select))
+    /// <summary>
+    /// Gets or sets the minimum size of the key text. Useful for aligning the key text with other <see cref="Shortcut"/>s.
+    /// </summary>
+    public int MinimumKeyTextSize
     {
-        return CommandView.InvokeCommand (Command.Select, ctx.Key, ctx.KeyBinding);
+        get => _minimumKeyTextSize;
+        set
+        {
+            if (value == _minimumKeyTextSize)
+            {
+                //return;
+            }
+
+            _minimumKeyTextSize = value;
+            SetKeyViewDefaultLayout ();
+            CommandView.SetNeedsLayout ();
+            HelpView.SetNeedsLayout ();
+            KeyView.SetNeedsLayout ();
+            SetSubViewNeedsDisplay ();
+        }
     }
-    return false;
 
-}
+    private int GetMinimumKeyViewSize () { return MinimumKeyTextSize; }
 
-
-#region Focus
-
-/// <inheritdoc/>
-public override ColorScheme ColorScheme
-{
-    get => base.ColorScheme;
-    set
+    private void SetKeyViewDefaultLayout ()
+    {
+        KeyView.Margin.Thickness = GetMarginThickness ();
+        KeyView.X = Pos.Align (Alignment.End, AlignmentModes);
+        KeyView.Y = 0; //Pos.Center ();
+        KeyView.Width = Dim.Auto (DimAutoStyle.Text, Dim.Func (GetMinimumKeyViewSize));
+        KeyView.Height = CommandView?.Visible == true ? Dim.Height (CommandView) : 1;
+
+        KeyView.Visible = true;
+
+        // Right align the text in the keyview
+        KeyView.TextAlignment = Alignment.End;
+        KeyView.VerticalTextAlignment = Alignment.Center;
+        KeyView.KeyBindings.Clear ();
+    }
+
+    private void UpdateKeyBinding ()
+    {
+        if (Key != null)
+        {
+            // Disable the command view key bindings
+            CommandView.KeyBindings.Remove (Key);
+            CommandView.KeyBindings.Remove (CommandView.HotKey);
+
+            if (KeyBindingScope.FastHasFlags (KeyBindingScope.Application))
+            {
+                Application.KeyBindings.Remove (Key);
+                Application.KeyBindings.Add (Key, this, Command.Accept);
+            }
+            else
+            {
+                KeyBindings.Remove (Key);
+                KeyBindings.Add (Key, KeyBindingScope | KeyBindingScope.HotKey, Command.Accept);
+            }
+        }
+    }
+
+    #endregion Key
+
+    #region Accept Handling
+
+    /// <summary>
+    ///     Called when the <see cref="Command.Accept"/> command is received. This
+    ///     occurs
+    ///     - if the user clicks anywhere on the shortcut with the mouse
+    ///     - if the user presses Key
+    ///     - if the user presses the HotKey specified by CommandView
+    ///     - if HasFocus and the user presses Space or Enter (or any other key bound to Command.Accept).
+    /// </summary>
+    protected bool? OnAccept (CommandContext ctx)
+    {
+        var cancel = false;
+
+        switch (ctx.KeyBinding?.Scope)
+        {
+            case KeyBindingScope.Application:
+                cancel = base.OnAccept () == true;
+
+                break;
+
+            case KeyBindingScope.Focused:
+                base.OnAccept ();
+
+                // cancel if we're focused
+                cancel = true;
+
+                break;
+
+            case KeyBindingScope.HotKey:
+                cancel = base.OnAccept () == true;
+
+                if (CanFocus)
+                {
+                    SetFocus ();
+                    cancel = true;
+                }
+
+                break;
+
+            default:
+                // Mouse
+                cancel = base.OnAccept () == true;
+
+                break;
+        }
+
+        CommandView.InvokeCommand (Command.Accept, ctx.Key, ctx.KeyBinding);
+
+        if (Action is { })
+        {
+            Action.Invoke ();
+            // Assume if there's a subscriber to Action, it's handled.
+            cancel = true;
+        }
+
+        return cancel;
+    }
+
+    /// <summary>
+    ///     Gets or sets the action to be invoked when the shortcut key is pressed or the shortcut is clicked on with the
+    ///     mouse.
+    /// </summary>
+    /// <remarks>
+    ///     Note, the <see cref="View.Accept"/> event is fired first, and if cancelled, the event will not be invoked.
+    /// </remarks>
+    [CanBeNull]
+    public Action Action { get; set; }
+
+    #endregion Accept Handling
+
+    private bool? OnSelect (CommandContext ctx)
+    {
+        if (CommandView.GetSupportedCommands ().Contains (Command.Select))
+        {
+            return CommandView.InvokeCommand (Command.Select, ctx.Key, ctx.KeyBinding);
+        }
+        return false;
+
+    }
+
+
+    #region Focus
+
+    /// <inheritdoc/>
+    public override ColorScheme ColorScheme
+    {
+        get => base.ColorScheme;
+        set
+        {
+            base.ColorScheme = value;
+            SetColors ();
+        }
+    }
+
+    /// <summary>
+    /// </summary>
+    internal void SetColors ()
+    {
+        // Border should match superview.
+        Border.ColorScheme = SuperView?.ColorScheme;
+
+        if (HasFocus)
+        {
+            // When we have focus, we invert the colors
+            base.ColorScheme = new (base.ColorScheme)
+            {
+                Normal = base.ColorScheme.Focus,
+                HotNormal = base.ColorScheme.HotFocus,
+                HotFocus = base.ColorScheme.HotNormal,
+                Focus = base.ColorScheme.Normal
+            };
+        }
+        else
+        {
+            base.ColorScheme = SuperView?.ColorScheme ?? base.ColorScheme;
+        }
+
+        // Set KeyView's colors to show "hot"
+        if (IsInitialized && base.ColorScheme is { })
+        {
+            var cs = new ColorScheme (base.ColorScheme)
+            {
+                Normal = base.ColorScheme.HotNormal,
+                HotNormal = base.ColorScheme.Normal
+            };
+            KeyView.ColorScheme = cs;
+        }
+    }
+
+    View _lastFocusedView;
+    /// <inheritdoc/>
+    public override bool OnEnter (View view)
     {
-        base.ColorScheme = value;
         SetColors ();
+        _lastFocusedView = view;
+
+        return base.OnEnter (view);
     }
-}
 
-/// <summary>
-/// </summary>
-internal void SetColors ()
-{
-    // Border should match superview.
-    Border.ColorScheme = SuperView?.ColorScheme;
-
-    if (HasFocus)
+    /// <inheritdoc/>
+    public override bool OnLeave (View view)
     {
-        // When we have focus, we invert the colors
-        base.ColorScheme = new (base.ColorScheme)
+        SetColors ();
+        _lastFocusedView = this;
+
+        return base.OnLeave (view);
+    }
+
+    #endregion Focus
+
+    /// <inheritdoc/>
+    protected override void Dispose (bool disposing)
+    {
+        if (disposing)
         {
-            Normal = base.ColorScheme.Focus,
-            HotNormal = base.ColorScheme.HotFocus,
-            HotFocus = base.ColorScheme.HotNormal,
-            Focus = base.ColorScheme.Normal
-        };
-    }
-    else
-    {
-        base.ColorScheme = SuperView?.ColorScheme ?? base.ColorScheme;
-    }
+            if (CommandView?.IsAdded == false)
+            {
+                CommandView.Dispose ();
+            }
 
-    // Set KeyView's colors to show "hot"
-    if (IsInitialized && base.ColorScheme is { })
-    {
-        var cs = new ColorScheme (base.ColorScheme)
-        {
-            Normal = base.ColorScheme.HotNormal,
-            HotNormal = base.ColorScheme.Normal
-        };
-        KeyView.ColorScheme = cs;
-    }
-}
+            if (HelpView?.IsAdded == false)
+            {
+                HelpView.Dispose ();
+            }
 
-View _lastFocusedView;
-/// <inheritdoc/>
-public override bool OnEnter (View view)
-{
-    SetColors ();
-    _lastFocusedView = view;
-
-    return base.OnEnter (view);
-}
-
-/// <inheritdoc/>
-public override bool OnLeave (View view)
-{
-    SetColors ();
-    _lastFocusedView = this;
-
-    return base.OnLeave (view);
-}
-
-#endregion Focus
-
-/// <inheritdoc/>
-protected override void Dispose (bool disposing)
-{
-    if (disposing)
-    {
-        if (CommandView?.IsAdded == false)
-        {
-            CommandView.Dispose ();
+            if (KeyView?.IsAdded == false)
+            {
+                KeyView.Dispose ();
+            }
         }
 
-        if (HelpView?.IsAdded == false)
-        {
-            HelpView.Dispose ();
-        }
-
-        if (KeyView?.IsAdded == false)
-        {
-            KeyView.Dispose ();
-        }
+        base.Dispose (disposing);
     }
-
-    base.Dispose (disposing);
-}
 }
diff --git a/Terminal.Gui/Views/Slider.cs b/Terminal.Gui/Views/Slider.cs
index 61ac401d6..73e479b74 100644
--- a/Terminal.Gui/Views/Slider.cs
+++ b/Terminal.Gui/Views/Slider.cs
@@ -1454,9 +1454,13 @@ public class Slider<T> : View
             KeyBindings.Add (Key.CursorUp.WithCtrl, Command.LeftExtend);
         }
 
+        KeyBindings.Remove (Key.Home);
         KeyBindings.Add (Key.Home, Command.LeftHome);
+        KeyBindings.Remove (Key.End);
         KeyBindings.Add (Key.End, Command.RightEnd);
+        KeyBindings.Remove (Key.Enter);
         KeyBindings.Add (Key.Enter, Command.Accept);
+        KeyBindings.Remove (Key.Space);
         KeyBindings.Add (Key.Space, Command.Select);
     }
 
diff --git a/Terminal.Gui/Views/StatusBar.cs b/Terminal.Gui/Views/StatusBar.cs
index b4df14e6b..ce3ad268a 100644
--- a/Terminal.Gui/Views/StatusBar.cs
+++ b/Terminal.Gui/Views/StatusBar.cs
@@ -65,8 +65,6 @@ public class StatusBar : Bar
 
         if (view is Shortcut shortcut)
         {
-            shortcut.KeyBindingScope = KeyBindingScope.Application;
-
             // TODO: not happy about using AlignmentModes for this. Too implied.
             // TODO: instead, add a property (a style enum?) to Shortcut to control this
             shortcut.AlignmentModes = AlignmentModes.EndToStart;
diff --git a/Terminal.Gui/Views/TableView/CheckBoxTableSourceWrapper.cs b/Terminal.Gui/Views/TableView/CheckBoxTableSourceWrapper.cs
index 7d2379af8..8be294c1a 100644
--- a/Terminal.Gui/Views/TableView/CheckBoxTableSourceWrapper.cs
+++ b/Terminal.Gui/Views/TableView/CheckBoxTableSourceWrapper.cs
@@ -26,7 +26,7 @@ public abstract class CheckBoxTableSourceWrapperBase : ITableSource
         Wrapping = toWrap;
         this.tableView = tableView;
 
-        tableView.KeyBindings.Add (Key.Space, Command.Select);
+        tableView.KeyBindings.ReplaceCommands (Key.Space, Command.Select);
 
         tableView.MouseClick += TableView_MouseClick;
         tableView.CellToggled += TableView_CellToggled;
diff --git a/Terminal.Gui/Views/TableView/TableView.cs b/Terminal.Gui/Views/TableView/TableView.cs
index 0807991d5..67974349f 100644
--- a/Terminal.Gui/Views/TableView/TableView.cs
+++ b/Terminal.Gui/Views/TableView/TableView.cs
@@ -319,7 +319,7 @@ public class TableView : View
         {
             if (cellActivationKey != value)
             {
-                KeyBindings.Replace (cellActivationKey, value);
+                KeyBindings.ReplaceKey (cellActivationKey, value);
 
                 // of API user is mixing and matching old and new methods of keybinding then they may have lost
                 // the old binding (e.g. with ClearKeybindings) so KeyBindings.Replace alone will fail
diff --git a/Terminal.Gui/Views/TextField.cs b/Terminal.Gui/Views/TextField.cs
index bdcb92dd5..b5d14db0a 100644
--- a/Terminal.Gui/Views/TextField.cs
+++ b/Terminal.Gui/Views/TextField.cs
@@ -1332,7 +1332,10 @@ public class TextField : View
                                );
     }
 
-    private void ContextMenu_KeyChanged (object sender, KeyChangedEventArgs e) { KeyBindings.Replace (e.OldKey.KeyCode, e.NewKey.KeyCode); }
+    private void ContextMenu_KeyChanged (object sender, KeyChangedEventArgs e)
+    {
+        KeyBindings.ReplaceKey (e.OldKey.KeyCode, e.NewKey.KeyCode);
+    }
 
     private List<Rune> DeleteSelectedText ()
     {
diff --git a/Terminal.Gui/Views/TextValidateField.cs b/Terminal.Gui/Views/TextValidateField.cs
index 35779d59b..045f6df3f 100644
--- a/Terminal.Gui/Views/TextValidateField.cs
+++ b/Terminal.Gui/Views/TextValidateField.cs
@@ -464,7 +464,6 @@ namespace Terminal.Gui
             KeyBindings.Add (Key.Home, Command.LeftHome);
             KeyBindings.Add (Key.End, Command.RightEnd);
 
-            KeyBindings.Add (Key.Delete, Command.DeleteCharRight);
             KeyBindings.Add (Key.Delete, Command.DeleteCharRight);
 
             KeyBindings.Add (Key.Backspace, Command.DeleteCharLeft);
diff --git a/Terminal.Gui/Views/TextView.cs b/Terminal.Gui/Views/TextView.cs
index bea620aee..598f78961 100644
--- a/Terminal.Gui/Views/TextView.cs
+++ b/Terminal.Gui/Views/TextView.cs
@@ -2369,8 +2369,8 @@ public class TextView : View
                    );
         AddCommand (Command.Tab, () => ProcessTab ());
         AddCommand (Command.BackTab, () => ProcessBackTab ());
-        AddCommand (Command.NextView, () => ProcessMoveNextView ());
-        AddCommand (Command.PreviousView, () => ProcessMovePreviousView ());
+        //AddCommand (Command.NextView, () => ProcessMoveNextView ());
+        //AddCommand (Command.PreviousView, () => ProcessMovePreviousView ());
 
         AddCommand (
                     Command.Undo,
@@ -2503,11 +2503,11 @@ public class TextView : View
         KeyBindings.Add (Key.Tab, Command.Tab);
         KeyBindings.Add (Key.Tab.WithShift, Command.BackTab);
 
-        KeyBindings.Add (Key.Tab.WithCtrl, Command.NextView);
-        KeyBindings.Add (Application.AlternateForwardKey, Command.NextView);
+        //KeyBindings.Add (Key.Tab.WithCtrl, Command.NextView);
+        //KeyBindings.Add (Application.AlternateForwardKey, Command.NextView);
 
-        KeyBindings.Add (Key.Tab.WithCtrl.WithShift, Command.PreviousView);
-        KeyBindings.Add (Application.AlternateBackwardKey, Command.PreviousView);
+        //KeyBindings.Add (Key.Tab.WithCtrl.WithShift, Command.PreviousView);
+        //KeyBindings.Add (Application.AlternateBackwardKey, Command.PreviousView);
 
         KeyBindings.Add (Key.Z.WithCtrl, Command.Undo);
         KeyBindings.Add (Key.R.WithCtrl, Command.Redo);
@@ -4318,7 +4318,7 @@ public class TextView : View
         DoNeededAction ();
     }
 
-    private void ContextMenu_KeyChanged (object sender, KeyChangedEventArgs e) { KeyBindings.Replace (e.OldKey, e.NewKey); }
+    private void ContextMenu_KeyChanged (object sender, KeyChangedEventArgs e) { KeyBindings.ReplaceKey (e.OldKey, e.NewKey); }
 
     private bool DeleteTextBackwards ()
     {
@@ -6393,8 +6393,8 @@ public class TextView : View
         _selectionStartRow = CurrentRow;
     }
 
-    private void Top_AlternateBackwardKeyChanged (object sender, KeyChangedEventArgs e) { KeyBindings.Replace (e.OldKey, e.NewKey); }
-    private void Top_AlternateForwardKeyChanged (object sender, KeyChangedEventArgs e) { KeyBindings.Replace (e.OldKey, e.NewKey); }
+    private void Top_AlternateBackwardKeyChanged (object sender, KeyChangedEventArgs e) { KeyBindings.ReplaceKey (e.OldKey, e.NewKey); }
+    private void Top_AlternateForwardKeyChanged (object sender, KeyChangedEventArgs e) { KeyBindings.ReplaceKey (e.OldKey, e.NewKey); }
 
     // Tries to snap the cursor to the tracking column
     private void TrackColumn ()
diff --git a/Terminal.Gui/Views/TimeField.cs b/Terminal.Gui/Views/TimeField.cs
index 5f303cc98..a473fdcea 100644
--- a/Terminal.Gui/Views/TimeField.cs
+++ b/Terminal.Gui/Views/TimeField.cs
@@ -58,26 +58,26 @@ public class TimeField : TextField
         AddCommand (Command.RightEnd, () => MoveEnd ());
         AddCommand (Command.Right, () => MoveRight ());
 
-        // Default keybindings for this view
-        KeyBindings.Add (Key.Delete, Command.DeleteCharRight);
-        KeyBindings.Add (Key.D.WithCtrl, Command.DeleteCharRight);
+        // Replace the key bindings defined in TextField
+        KeyBindings.ReplaceCommands (Key.Delete, Command.DeleteCharRight);
+        KeyBindings.ReplaceCommands (Key.D.WithCtrl, Command.DeleteCharRight);
 
-        KeyBindings.Add (Key.Backspace, Command.DeleteCharLeft);
+        KeyBindings.ReplaceCommands (Key.Backspace, Command.DeleteCharLeft);
 
-        KeyBindings.Add (Key.Home, Command.LeftHome);
-        KeyBindings.Add (Key.A.WithCtrl, Command.LeftHome);
+        KeyBindings.ReplaceCommands (Key.Home, Command.LeftHome);
+        KeyBindings.ReplaceCommands (Key.A.WithCtrl, Command.LeftHome);
 
-        KeyBindings.Add (Key.CursorLeft, Command.Left);
-        KeyBindings.Add (Key.B.WithCtrl, Command.Left);
+        KeyBindings.ReplaceCommands (Key.CursorLeft, Command.Left);
+        KeyBindings.ReplaceCommands (Key.B.WithCtrl, Command.Left);
 
-        KeyBindings.Add (Key.End, Command.RightEnd);
-        KeyBindings.Add (Key.E.WithCtrl, Command.RightEnd);
+        KeyBindings.ReplaceCommands (Key.End, Command.RightEnd);
+        KeyBindings.ReplaceCommands (Key.E.WithCtrl, Command.RightEnd);
 
-        KeyBindings.Add (Key.CursorRight, Command.Right);
-        KeyBindings.Add (Key.F.WithCtrl, Command.Right);
+        KeyBindings.ReplaceCommands (Key.CursorRight, Command.Right);
+        KeyBindings.ReplaceCommands (Key.F.WithCtrl, Command.Right);
 
 #if UNIX_KEY_BINDINGS
-        KeyBindings.Add (Key.D.WithAlt, Command.DeleteCharLeft);
+        KeyBindings.ReplaceCommands (Key.D.WithAlt, Command.DeleteCharLeft);
 #endif
     }
 
diff --git a/Terminal.Gui/Views/Toplevel.cs b/Terminal.Gui/Views/Toplevel.cs
index 0e7090492..fb31efb73 100644
--- a/Terminal.Gui/Views/Toplevel.cs
+++ b/Terminal.Gui/Views/Toplevel.cs
@@ -34,7 +34,7 @@ public partial class Toplevel : View
 
         ColorScheme = Colors.ColorSchemes ["TopLevel"];
 
-        ConfigureKeyBindings ();
+        //ConfigureKeyBindings ();
 
         MouseClick += Toplevel_MouseClick;
     }
@@ -188,7 +188,7 @@ public partial class Toplevel : View
     /// <param name="e"></param>
     public virtual void OnAlternateBackwardKeyChanged (KeyChangedEventArgs e)
     {
-        KeyBindings.Replace (e.OldKey, e.NewKey);
+        KeyBindings.ReplaceKey (e.OldKey, e.NewKey);
         AlternateBackwardKeyChanged?.Invoke (this, e);
     }
 
@@ -197,7 +197,7 @@ public partial class Toplevel : View
     /// <param name="e"></param>
     public virtual void OnAlternateForwardKeyChanged (KeyChangedEventArgs e)
     {
-        KeyBindings.Replace (e.OldKey, e.NewKey);
+        KeyBindings.ReplaceKey (e.OldKey, e.NewKey);
         AlternateForwardKeyChanged?.Invoke (this, e);
     }
 
@@ -205,7 +205,7 @@ public partial class Toplevel : View
     /// <param name="e"></param>
     public virtual void OnQuitKeyChanged (KeyChangedEventArgs e)
     {
-        KeyBindings.Replace (e.OldKey, e.NewKey);
+        KeyBindings.ReplaceKey (e.OldKey, e.NewKey);
         QuitKeyChanged?.Invoke (this, e);
     }
 
@@ -650,7 +650,7 @@ public partial class Toplevel : View
     /// <summary>
     ///     Moves the focus to 
     /// </summary>
-    private void MoveNextView ()
+    internal void MoveNextView ()
     {
         View old = GetDeepestFocusedSubview (Focused);
 
@@ -670,7 +670,7 @@ public partial class Toplevel : View
         }
     }
 
-    private void MoveNextViewOrTop ()
+    internal void MoveNextViewOrTop ()
     {
         if (Application.OverlappedTop is null)
         {
@@ -691,7 +691,7 @@ public partial class Toplevel : View
         }
     }
 
-    private void MovePreviousView ()
+    internal void MovePreviousView ()
     {
         View old = GetDeepestFocusedSubview (Focused);
 
@@ -711,7 +711,7 @@ public partial class Toplevel : View
         }
     }
 
-    private void MovePreviousViewOrTop ()
+    internal void MovePreviousViewOrTop ()
     {
         if (Application.OverlappedTop is null)
         {
diff --git a/Terminal.Gui/Views/TreeView/TreeView.cs b/Terminal.Gui/Views/TreeView/TreeView.cs
index f2039d9c6..5fbde234c 100644
--- a/Terminal.Gui/Views/TreeView/TreeView.cs
+++ b/Terminal.Gui/Views/TreeView/TreeView.cs
@@ -352,7 +352,7 @@ public class TreeView<T> : View, ITreeView where T : class
         {
             if (objectActivationKey != value)
             {
-                KeyBindings.Replace (ObjectActivationKey, value);
+                KeyBindings.ReplaceKey (ObjectActivationKey, value);
                 objectActivationKey = value;
             }
         }
diff --git a/UICatalog/Scenarios/KeyBindings.cs b/UICatalog/Scenarios/KeyBindings.cs
index 8814a1991..d62444543 100644
--- a/UICatalog/Scenarios/KeyBindings.cs
+++ b/UICatalog/Scenarios/KeyBindings.cs
@@ -80,13 +80,10 @@ public sealed class KeyBindings : Scenario
         };
         appWindow.Add (appBindingsListView);
 
-        foreach (var appBinding in Application.GetKeyBindings ())
+        foreach (var appBinding in Application.KeyBindings.Bindings)
         {
-            foreach (var view in appBinding.Value)
-            {
-                var commands = view.KeyBindings.GetCommands (appBinding.Key);
-                appBindings.Add ($"{appBinding.Key} -> {view.GetType ().Name} - {commands [0]}");
-            }
+                var commands = Application.KeyBindings.GetCommands (appBinding.Key);
+                appBindings.Add ($"{appBinding.Key} -> {appBinding.Value.BoundView?.GetType ().Name} - {commands [0]}");
         }
 
         ObservableCollection<string> hotkeyBindings = new ();
@@ -153,10 +150,10 @@ public sealed class KeyBindings : Scenario
 
     private void AppWindow_Leave (object sender, FocusEventArgs e)
     {
-        //foreach (var binding in Application.Top.MostFocused.KeyBindings.Bindings.Where (b => b.Value.Scope == KeyBindingScope.Focused))
-        //{
-        //    _focusedBindings.Add ($"{binding.Key} -> {binding.Value.Commands [0]}");
-        //}
+        foreach (var binding in Application.Top.MostFocused.KeyBindings.Bindings.Where (b => b.Value.Scope == KeyBindingScope.Focused))
+        {
+            _focusedBindings.Add ($"{binding.Key} -> {binding.Value.Commands [0]}");
+        }
     }
 }
 
@@ -166,28 +163,34 @@ public class KeyBindingsDemo : View
     {
         CanFocus = true;
 
+
+        AddCommand (Command.Save, ctx =>
+                                 {
+                                     MessageBox.Query ($"{ctx.KeyBinding?.Scope}", $"Key: {ctx.Key}\nCommand: {ctx.Command}", buttons: "Ok");
+                                     return true;
+                                 });
         AddCommand (Command.New, ctx =>
                                 {
-                                    MessageBox.Query ("Hi", $"Key: {ctx.Key}\nCommand: {ctx.Command}", buttons: "Ok");
-
+                                    MessageBox.Query ($"{ctx.KeyBinding?.Scope}", $"Key: {ctx.Key}\nCommand: {ctx.Command}", buttons: "Ok");
                                     return true;
                                 });
         AddCommand (Command.HotKey, ctx =>
         {
-            MessageBox.Query ("Hi", $"Key: {ctx.Key}\nCommand: {ctx.Command}", buttons: "Ok");
+            MessageBox.Query ($"{ctx.KeyBinding?.Scope}", $"Key: {ctx.Key}\nCommand: {ctx.Command}", buttons: "Ok");
             SetFocus ();
             return true;
         });
 
-        KeyBindings.Add (Key.F3, KeyBindingScope.Focused, Command.New);
-        KeyBindings.Add (Key.F4, KeyBindingScope.Application, Command.New);
-
+        KeyBindings.Add (Key.F2, KeyBindingScope.Focused, Command.Save);
+        KeyBindings.Add (Key.F3, Command.New); // same as specifying KeyBindingScope.Focused
+        Application.KeyBindings.Add (Key.F4, this, Command.New);
 
         AddCommand (Command.QuitToplevel, ctx =>
                                          {
+                                             MessageBox.Query ($"{ctx.KeyBinding?.Scope}", $"Key: {ctx.Key}\nCommand: {ctx.Command}", buttons: "Ok");
                                              Application.RequestStop ();
                                              return true;
                                          });
-        KeyBindings.Add (Key.Q.WithCtrl, KeyBindingScope.Application, Command.QuitToplevel);
+        Application.KeyBindings.Add (Key.Q.WithAlt, this, Command.QuitToplevel);
     }
 }
diff --git a/UICatalog/Scenarios/ListColumns.cs b/UICatalog/Scenarios/ListColumns.cs
index 0f45b1e5d..12c9619cf 100644
--- a/UICatalog/Scenarios/ListColumns.cs
+++ b/UICatalog/Scenarios/ListColumns.cs
@@ -254,7 +254,7 @@ public class ListColumns : Scenario
         // if user clicks the mouse in TableView
         _listColView.MouseClick += (s, e) => { _listColView.ScreenToCell (e.MouseEvent.Position, out int? clickedCol); };
 
-        _listColView.KeyBindings.Add (Key.Space, Command.Accept);
+        _listColView.KeyBindings.ReplaceCommands (Key.Space, Command.Accept);
 
         top.Add (appWindow);
 
diff --git a/UICatalog/Scenarios/TableEditor.cs b/UICatalog/Scenarios/TableEditor.cs
index df86aceaf..ca36671ce 100644
--- a/UICatalog/Scenarios/TableEditor.cs
+++ b/UICatalog/Scenarios/TableEditor.cs
@@ -769,7 +769,7 @@ public class TableEditor : Scenario
                                      }
                                  };
 
-        _tableView.KeyBindings.Add (Key.Space, Command.Accept);
+        _tableView.KeyBindings.ReplaceCommands (Key.Space, Command.Accept);
 
         // Run - Start the application.
         Application.Run (appWindow);
diff --git a/UICatalog/UICatalog.cs b/UICatalog/UICatalog.cs
index f9ac4a503..dd18f0bd1 100644
--- a/UICatalog/UICatalog.cs
+++ b/UICatalog/UICatalog.cs
@@ -605,7 +605,9 @@ internal class UICatalogApp
             ScenarioList.CellActivated += ScenarioView_OpenSelectedItem;
 
             // TableView typically is a grid where nav keys are biased for moving left/right.
+            ScenarioList.KeyBindings.Remove (Key.Home);
             ScenarioList.KeyBindings.Add (Key.Home, Command.TopHome);
+            ScenarioList.KeyBindings.Remove (Key.End);
             ScenarioList.KeyBindings.Add (Key.End, Command.BottomEnd);
 
             // Ideally, TableView.MultiSelect = false would turn off any keybindings for
diff --git a/UnitTests/Application/ApplicationTests.cs b/UnitTests/Application/ApplicationTests.cs
index 6363233a9..f8f1f8029 100644
--- a/UnitTests/Application/ApplicationTests.cs
+++ b/UnitTests/Application/ApplicationTests.cs
@@ -199,7 +199,7 @@ public class ApplicationTests
             Assert.Null (Application._mouseEnteredView);
 
             // Keyboard
-            Assert.Empty (Application.GetViewsWithKeyBindings ());
+            Assert.Empty (Application.GetViewKeyBindings ());
 
             // Events - Can't check
             //Assert.Null (Application.NotifyNewRunState);
@@ -233,7 +233,7 @@ public class ApplicationTests
         Application.AlternateBackwardKey = Key.A;
         Application.AlternateForwardKey = Key.B;
         Application.QuitKey = Key.C;
-        Application.AddKeyBinding (Key.A, new View ());
+        Application.KeyBindings.Add (Key.A, KeyBindingScope.Application, Command.Cancel);
 
         //Application.OverlappedChildren = new List<View> ();
         //Application.OverlappedTop = 
diff --git a/UnitTests/Application/KeyboardTests.cs b/UnitTests/Application/KeyboardTests.cs
index 3483b8396..4dfb5b11a 100644
--- a/UnitTests/Application/KeyboardTests.cs
+++ b/UnitTests/Application/KeyboardTests.cs
@@ -71,7 +71,7 @@ public class KeyboardTests
         // After Init
         Assert.Equal (Key.Esc, Application.QuitKey);
 
-        Application.Shutdown();
+        Application.Shutdown ();
     }
 
     private object _timeoutLock;
@@ -200,62 +200,62 @@ public class KeyboardTests
                                      Assert.True (v1.HasFocus);
 
                                      // Using default keys.
-                                     top.NewKeyDownEvent (Key.Tab.WithCtrl);
+                                     Application.OnKeyDown (Key.Tab.WithCtrl);
                                      Assert.True (v2.HasFocus);
-                                     top.NewKeyDownEvent (Key.Tab.WithCtrl);
+                                     Application.OnKeyDown (Key.Tab.WithCtrl);
                                      Assert.True (v3.HasFocus);
-                                     top.NewKeyDownEvent (Key.Tab.WithCtrl);
+                                     Application.OnKeyDown (Key.Tab.WithCtrl);
                                      Assert.True (v4.HasFocus);
-                                     top.NewKeyDownEvent (Key.Tab.WithCtrl);
+                                     Application.OnKeyDown (Key.Tab.WithCtrl);
                                      Assert.True (v1.HasFocus);
 
-                                     top.NewKeyDownEvent (Key.Tab.WithShift.WithCtrl);
+                                     Application.OnKeyDown (Key.Tab.WithShift.WithCtrl);
                                      Assert.True (v4.HasFocus);
-                                     top.NewKeyDownEvent (Key.Tab.WithShift.WithCtrl);
+                                     Application.OnKeyDown (Key.Tab.WithShift.WithCtrl);
                                      Assert.True (v3.HasFocus);
-                                     top.NewKeyDownEvent (Key.Tab.WithShift.WithCtrl);
+                                     Application.OnKeyDown (Key.Tab.WithShift.WithCtrl);
                                      Assert.True (v2.HasFocus);
-                                     top.NewKeyDownEvent (Key.Tab.WithShift.WithCtrl);
+                                     Application.OnKeyDown (Key.Tab.WithShift.WithCtrl);
                                      Assert.True (v1.HasFocus);
 
-                                     top.NewKeyDownEvent (Key.PageDown.WithCtrl);
+                                     Application.OnKeyDown (Key.PageDown.WithCtrl);
                                      Assert.True (v2.HasFocus);
-                                     top.NewKeyDownEvent (Key.PageDown.WithCtrl);
+                                     Application.OnKeyDown (Key.PageDown.WithCtrl);
                                      Assert.True (v3.HasFocus);
-                                     top.NewKeyDownEvent (Key.PageDown.WithCtrl);
+                                     Application.OnKeyDown (Key.PageDown.WithCtrl);
                                      Assert.True (v4.HasFocus);
-                                     top.NewKeyDownEvent (Key.PageDown.WithCtrl);
+                                     Application.OnKeyDown (Key.PageDown.WithCtrl);
                                      Assert.True (v1.HasFocus);
 
-                                     top.NewKeyDownEvent (Key.PageUp.WithCtrl);
+                                     Application.OnKeyDown (Key.PageUp.WithCtrl);
                                      Assert.True (v4.HasFocus);
-                                     top.NewKeyDownEvent (Key.PageUp.WithCtrl);
+                                     Application.OnKeyDown (Key.PageUp.WithCtrl);
                                      Assert.True (v3.HasFocus);
-                                     top.NewKeyDownEvent (Key.PageUp.WithCtrl);
+                                     Application.OnKeyDown (Key.PageUp.WithCtrl);
                                      Assert.True (v2.HasFocus);
-                                     top.NewKeyDownEvent (Key.PageUp.WithCtrl);
+                                     Application.OnKeyDown (Key.PageUp.WithCtrl);
                                      Assert.True (v1.HasFocus);
 
                                      // Using another's alternate keys.
                                      Application.AlternateForwardKey = Key.F7;
                                      Application.AlternateBackwardKey = Key.F6;
 
-                                     top.NewKeyDownEvent (Key.F7);
+                                     Application.OnKeyDown (Key.F7);
                                      Assert.True (v2.HasFocus);
-                                     top.NewKeyDownEvent (Key.F7);
+                                     Application.OnKeyDown (Key.F7);
                                      Assert.True (v3.HasFocus);
-                                     top.NewKeyDownEvent (Key.F7);
+                                     Application.OnKeyDown (Key.F7);
                                      Assert.True (v4.HasFocus);
-                                     top.NewKeyDownEvent (Key.F7);
+                                     Application.OnKeyDown (Key.F7);
                                      Assert.True (v1.HasFocus);
 
-                                     top.NewKeyDownEvent (Key.F6);
+                                     Application.OnKeyDown (Key.F6);
                                      Assert.True (v4.HasFocus);
-                                     top.NewKeyDownEvent (Key.F6);
+                                     Application.OnKeyDown (Key.F6);
                                      Assert.True (v3.HasFocus);
-                                     top.NewKeyDownEvent (Key.F6);
+                                     Application.OnKeyDown (Key.F6);
                                      Assert.True (v2.HasFocus);
-                                     top.NewKeyDownEvent (Key.F6);
+                                     Application.OnKeyDown (Key.F6);
                                      Assert.True (v1.HasFocus);
 
                                      Application.RequestStop ();
@@ -321,14 +321,14 @@ public class KeyboardTests
         Assert.True (win2.HasFocus);
         Assert.Equal ("win2", ((Window)top.Subviews [^1]).Title);
 
-        top.NewKeyDownEvent (Key.Tab.WithCtrl);
+        Application.OnKeyDown (Key.Tab.WithCtrl);
         Assert.True (win2.CanFocus);
         Assert.False (win.HasFocus);
         Assert.True (win2.CanFocus);
         Assert.True (win2.HasFocus);
         Assert.Equal ("win2", ((Window)top.Subviews [^1]).Title);
 
-        top.NewKeyDownEvent (Key.Tab.WithCtrl);
+        Application.OnKeyDown (Key.Tab.WithCtrl);
         Assert.False (win.CanFocus);
         Assert.False (win.HasFocus);
         Assert.True (win2.CanFocus);
@@ -374,14 +374,14 @@ public class KeyboardTests
         Assert.False (win2.HasFocus);
         Assert.Equal ("win", ((Window)top.Subviews [^1]).Title);
 
-        top.NewKeyDownEvent (Key.Tab.WithCtrl);
+        Application.OnKeyDown (Key.Tab.WithCtrl);
         Assert.True (win.CanFocus);
         Assert.False (win.HasFocus);
         Assert.True (win2.CanFocus);
         Assert.True (win2.HasFocus);
         Assert.Equal ("win2", ((Window)top.Subviews [^1]).Title);
 
-        top.NewKeyDownEvent (Key.Tab.WithCtrl);
+        Application.OnKeyDown (Key.Tab.WithCtrl);
         Assert.True (win.CanFocus);
         Assert.True (win.HasFocus);
         Assert.True (win2.CanFocus);
@@ -496,21 +496,21 @@ public class KeyboardTests
         Application.Begin (top);
 
         Application.OnKeyDown (Key.A);
-        Assert.True (invoked);
+        Assert.False (invoked);
         Assert.True (view.ApplicationCommand);
 
         invoked = false;
         view.ApplicationCommand = false;
-        view.KeyBindings.Remove (KeyCode.A);
+        Application.KeyBindings.Remove (KeyCode.A); 
         Application.OnKeyDown (Key.A); // old
         Assert.False (invoked);
         Assert.False (view.ApplicationCommand);
-        view.KeyBindings.Add (Key.A.WithCtrl, KeyBindingScope.Application, Command.Save);
+        Application.KeyBindings.Add (Key.A.WithCtrl, view, Command.Save);
         Application.OnKeyDown (Key.A); // old
         Assert.False (invoked);
         Assert.False (view.ApplicationCommand);
         Application.OnKeyDown (Key.A.WithCtrl); // new
-        Assert.True (invoked);
+        Assert.False (invoked);
         Assert.True (view.ApplicationCommand);
 
         invoked = false;
@@ -556,70 +556,60 @@ public class KeyboardTests
         top.Dispose ();
     }
 
+    [Fact]
+    [AutoInitShutdown]
+    public void KeyBinding_Application_KeyBindings_Add_Adds ()
+    {
+        Application.KeyBindings.Add (Key.A, KeyBindingScope.Application, Command.Accept);
+        Application.KeyBindings.Add (Key.B, KeyBindingScope.Application, Command.Accept);
+
+        Assert.True (Application.KeyBindings.TryGet (Key.A, out var binding));
+        Assert.Null (binding.BoundView);
+        Assert.True (Application.KeyBindings.TryGet (Key.B, out binding));
+        Assert.Null (binding.BoundView);
+    }
 
     [Fact]
     [AutoInitShutdown]
-    public void KeyBinding_AddKeyBinding_Adds ()
+    public void KeyBinding_View_KeyBindings_Add_Adds ()
     {
         View view1 = new ();
-        Application.AddKeyBinding (Key.A, view1);
+        Application.KeyBindings.Add (Key.A, view1, Command.Accept);
 
         View view2 = new ();
-        Application.AddKeyBinding (Key.A, view2);
+        Application.KeyBindings.Add (Key.B, view2, Command.Accept);
 
-        Assert.True (Application.TryGetKeyBindings (Key.A, out List<View> views));
-        Assert.Contains (view1, views);
-        Assert.Contains (view2, views);
-
-        Assert.False (Application.TryGetKeyBindings (Key.B, out List<View> _));
+        Assert.True (Application.KeyBindings.TryGet (Key.A, out var binding));
+        Assert.Equal (view1, binding.BoundView);
+        Assert.True (Application.KeyBindings.TryGet (Key.B, out binding));
+        Assert.Equal (view2, binding.BoundView);
     }
 
     [Fact]
     [AutoInitShutdown]
-    public void KeyBinding_ViewKeyBindings_Add_Adds ()
+    public void KeyBinding_Application_RemoveKeyBinding_Removes ()
     {
+        Application.KeyBindings.Add (Key.A, KeyBindingScope.Application, Command.Accept);
+
+        Assert.True (Application.KeyBindings.TryGet (Key.A, out _));
+
+        Application.KeyBindings.Remove (Key.A);
+        Assert.False (Application.KeyBindings.TryGet (Key.A, out _));
+    }
+
+    [Fact]
+    [AutoInitShutdown]
+    public void KeyBinding_View_KeyBindings_RemoveKeyBinding_Removes ()
+    {
+
         View view1 = new ();
-        view1.KeyBindings.Add (Key.A, KeyBindingScope.Application, Command.Save);
-        view1.KeyBindings.Add (Key.B, KeyBindingScope.HotKey, Command.Left);
-        Assert.Single (Application.GetViewsWithKeyBindings ());
+        Application.KeyBindings.Add (Key.A, view1, Command.Accept);
 
         View view2 = new ();
-        view2.KeyBindings.Add (Key.A, KeyBindingScope.Application, Command.Save);
-        view2.KeyBindings.Add (Key.B, KeyBindingScope.HotKey, Command.Left);
+        Application.KeyBindings.Add (Key.B, view1, Command.Accept);
 
-        Assert.True (Application.TryGetKeyBindings (Key.A, out List<View> views));
-        Assert.Contains (view1, views);
-        Assert.Contains (view2, views);
-
-        Assert.False (Application.TryGetKeyBindings (Key.B, out List<View> _));
-    }
-
-    [Fact]
-    [AutoInitShutdown]
-    public void KeyBinding_RemoveKeyBinding_Removes ()
-    {
-        View view1 = new ();
-        Application.AddKeyBinding (Key.A, view1);
-
-        Assert.True (Application.TryGetKeyBindings (Key.A, out List<View> views));
-        Assert.Contains (view1, views);
-
-        Application.RemoveKeyBinding (Key.A, view1);
-        Assert.False (Application.TryGetKeyBindings (Key.A, out List<View> _));
-    }
-
-    [Fact]
-    [AutoInitShutdown]
-    public void KeyBinding_ViewKeyBindings_RemoveKeyBinding_Removes ()
-    {
-        View view1 = new ();
-        view1.KeyBindings.Add (Key.A, KeyBindingScope.Application, Command.Save);
-
-        Assert.True (Application.TryGetKeyBindings (Key.A, out List<View> views));
-        Assert.Contains (view1, views);
-
-        view1.KeyBindings.Remove (Key.A);
-        Assert.False (Application.TryGetKeyBindings (Key.A, out List<View> _));
+        Application.KeyBindings.Remove (Key.A, view1);
+        Assert.False (Application.KeyBindings.TryGet (Key.A, out _));
     }
 
     // Test View for testing Application key Bindings
@@ -631,9 +621,9 @@ public class KeyboardTests
             AddCommand (Command.HotKey, () => HotKeyCommand = true);
             AddCommand (Command.Left, () => FocusedCommand = true);
 
-            KeyBindings.Add (Key.A, KeyBindingScope.Application, Command.Save);
+            Application.KeyBindings.Add (Key.A, this, Command.Save);
             HotKey = KeyCode.H;
-            KeyBindings.Add (Key.F, KeyBindingScope.Focused, Command.Left);
+            KeyBindings.Add (Key.F, Command.Left);
         }
 
         public bool ApplicationCommand { get; set; }
diff --git a/UnitTests/Input/KeyBindingTests.cs b/UnitTests/Input/KeyBindingTests.cs
index 73a1c6b00..bf3b007fd 100644
--- a/UnitTests/Input/KeyBindingTests.cs
+++ b/UnitTests/Input/KeyBindingTests.cs
@@ -21,12 +21,12 @@ public class KeyBindingTests
         var keyBindings = new KeyBindings ();
         Command [] commands = { Command.Right, Command.Left };
 
-        keyBindings.Add (Key.A, commands);
+        keyBindings.Add (Key.A, KeyBindingScope.Application, commands);
         Command [] resultCommands = keyBindings.GetCommands (Key.A);
         Assert.Contains (Command.Right, resultCommands);
         Assert.Contains (Command.Left, resultCommands);
 
-        keyBindings.Add (Key.B, commands);
+        keyBindings.Add (Key.B, KeyBindingScope.Application, commands);
         resultCommands = keyBindings.GetCommands (Key.B);
         Assert.Contains (Command.Right, resultCommands);
         Assert.Contains (Command.Left, resultCommands);
@@ -36,11 +36,11 @@ public class KeyBindingTests
     public void Add_Single_Adds ()
     {
         var keyBindings = new KeyBindings ();
-        keyBindings.Add (Key.A, Command.HotKey);
+        keyBindings.Add (Key.A, KeyBindingScope.Application, Command.HotKey);
         Command [] resultCommands = keyBindings.GetCommands (Key.A);
         Assert.Contains (Command.HotKey, resultCommands);
 
-        keyBindings.Add (Key.B, Command.HotKey);
+        keyBindings.Add (Key.B, KeyBindingScope.Application, Command.HotKey);
         resultCommands = keyBindings.GetCommands (Key.B);
         Assert.Contains (Command.HotKey, resultCommands);
     }
@@ -50,7 +50,7 @@ public class KeyBindingTests
     public void Clear_Clears ()
     {
         var keyBindings = new KeyBindings ();
-        keyBindings.Add (Key.B, Command.HotKey);
+        keyBindings.Add (Key.B, KeyBindingScope.Application, Command.HotKey);
         keyBindings.Clear ();
         Command [] resultCommands = keyBindings.GetCommands (Key.A);
         Assert.Empty (resultCommands);
@@ -78,7 +78,7 @@ public class KeyBindingTests
     public void GetCommands_WithCommands_ReturnsCommands ()
     {
         var keyBindings = new KeyBindings ();
-        keyBindings.Add (Key.A, Command.HotKey);
+        keyBindings.Add (Key.A, KeyBindingScope.Application, Command.HotKey);
         Command [] resultCommands = keyBindings.GetCommands (Key.A);
         Assert.Contains (Command.HotKey, resultCommands);
     }
@@ -88,8 +88,8 @@ public class KeyBindingTests
     {
         var keyBindings = new KeyBindings ();
         Command [] commands = { Command.Right, Command.Left };
-        keyBindings.Add (Key.A, commands);
-        keyBindings.Add (Key.B, commands);
+        keyBindings.Add (Key.A, KeyBindingScope.Application, commands);
+        keyBindings.Add (Key.B, KeyBindingScope.Application, commands);
         Command [] resultCommands = keyBindings.GetCommands (Key.A);
         Assert.Contains (Command.Right, resultCommands);
         Assert.Contains (Command.Left, resultCommands);
@@ -103,7 +103,7 @@ public class KeyBindingTests
     {
         var keyBindings = new KeyBindings ();
         Command [] commands = { Command.Right, Command.Left };
-        keyBindings.Add (Key.A, commands);
+        keyBindings.Add (Key.A, KeyBindingScope.Application, commands);
         Command [] resultCommands = keyBindings.GetCommands (Key.A);
         Assert.Contains (Command.Right, resultCommands);
         Assert.Contains (Command.Left, resultCommands);
@@ -114,10 +114,10 @@ public class KeyBindingTests
     {
         var keyBindings = new KeyBindings ();
         Command [] commands1 = { Command.Right, Command.Left };
-        keyBindings.Add (Key.A, commands1);
+        keyBindings.Add (Key.A, KeyBindingScope.Application, commands1);
 
         Command [] commands2 = { Command.LineUp, Command.LineDown };
-        keyBindings.Add (Key.B, commands2);
+        keyBindings.Add (Key.B, KeyBindingScope.Application, commands2);
 
         Key key = keyBindings.GetKeyFromCommands (commands1);
         Assert.Equal (Key.A, key);
@@ -133,7 +133,7 @@ public class KeyBindingTests
     public void GetKeyFromCommands_OneCommand ()
     {
         var keyBindings = new KeyBindings ();
-        keyBindings.Add (Key.A, Command.Right);
+        keyBindings.Add (Key.A, KeyBindingScope.Application, Command.Right);
 
         Key key = keyBindings.GetKeyFromCommands (Command.Right);
         Assert.Equal (Key.A, key);
@@ -154,66 +154,66 @@ public class KeyBindingTests
     public void GetKeyFromCommands_WithCommands_ReturnsKey ()
     {
         var keyBindings = new KeyBindings ();
-        keyBindings.Add (Key.A, Command.HotKey);
+        keyBindings.Add (Key.A, KeyBindingScope.Application, Command.HotKey);
         Key resultKey = keyBindings.GetKeyFromCommands (Command.HotKey);
         Assert.Equal (Key.A, resultKey);
     }
 
     // Add should not allow duplicates
     [Fact]
-    public void Add_Replaces_If_Exists ()
+    public void Add_Throws_If_Exists ()
     {
         var keyBindings = new KeyBindings ();
-        keyBindings.Add (Key.A, Command.HotKey);
-        keyBindings.Add (Key.A, Command.Accept);
+        keyBindings.Add (Key.A, KeyBindingScope.Application, Command.HotKey);
+        Assert.Throws<InvalidOperationException> (() => keyBindings.Add (Key.A, KeyBindingScope.Application, Command.Accept));
 
         Command [] resultCommands = keyBindings.GetCommands (Key.A);
-        Assert.DoesNotContain (Command.HotKey, resultCommands);
+        Assert.Contains (Command.HotKey, resultCommands);
 
         keyBindings = new ();
         keyBindings.Add (Key.A, KeyBindingScope.Focused, Command.HotKey);
-        keyBindings.Add (Key.A, KeyBindingScope.Focused, Command.Accept);
+        Assert.Throws<InvalidOperationException> (() => keyBindings.Add (Key.A, KeyBindingScope.Focused, Command.Accept));
 
         resultCommands = keyBindings.GetCommands (Key.A);
-        Assert.DoesNotContain (Command.HotKey, resultCommands);
+        Assert.Contains (Command.HotKey, resultCommands);
 
         keyBindings = new ();
         keyBindings.Add (Key.A, KeyBindingScope.HotKey, Command.HotKey);
-        keyBindings.Add (Key.A, KeyBindingScope.Focused, Command.Accept);
+        Assert.Throws<InvalidOperationException> (() => keyBindings.Add (Key.A, KeyBindingScope.Focused, Command.Accept));
 
         resultCommands = keyBindings.GetCommands (Key.A);
-        Assert.DoesNotContain (Command.HotKey, resultCommands);
+        Assert.Contains (Command.HotKey, resultCommands);
 
         keyBindings = new ();
         keyBindings.Add (Key.A, new KeyBinding (new [] { Command.HotKey }, KeyBindingScope.HotKey));
-        keyBindings.Add (Key.A, new KeyBinding (new [] { Command.Accept }, KeyBindingScope.HotKey));
+        Assert.Throws<InvalidOperationException> (() => keyBindings.Add (Key.A, new KeyBinding (new [] { Command.Accept }, KeyBindingScope.HotKey)));
 
         resultCommands = keyBindings.GetCommands (Key.A);
-        Assert.DoesNotContain (Command.HotKey, resultCommands);
+        Assert.Contains (Command.HotKey, resultCommands);
     }
 
     [Fact]
     public void Replace_Key ()
     {
         var keyBindings = new KeyBindings ();
-        keyBindings.Add (Key.A, Command.HotKey);
-        keyBindings.Add (Key.B, Command.HotKey);
-        keyBindings.Add (Key.C, Command.HotKey);
-        keyBindings.Add (Key.D, Command.HotKey);
+        keyBindings.Add (Key.A, KeyBindingScope.Application, Command.HotKey);
+        keyBindings.Add (Key.B, KeyBindingScope.Application, Command.HotKey);
+        keyBindings.Add (Key.C, KeyBindingScope.Application, Command.HotKey);
+        keyBindings.Add (Key.D, KeyBindingScope.Application, Command.HotKey);
 
-        keyBindings.Replace (Key.A, Key.E);
+        keyBindings.ReplaceKey (Key.A, Key.E);
         Assert.Empty (keyBindings.GetCommands (Key.A));
         Assert.Contains (Command.HotKey, keyBindings.GetCommands (Key.E));
 
-        keyBindings.Replace (Key.B, Key.F);
+        keyBindings.ReplaceKey (Key.B, Key.F);
         Assert.Empty (keyBindings.GetCommands (Key.B));
         Assert.Contains (Command.HotKey, keyBindings.GetCommands (Key.F));
 
-        keyBindings.Replace (Key.C, Key.G);
+        keyBindings.ReplaceKey (Key.C, Key.G);
         Assert.Empty (keyBindings.GetCommands (Key.C));
         Assert.Contains (Command.HotKey, keyBindings.GetCommands (Key.G));
 
-        keyBindings.Replace (Key.D, Key.H);
+        keyBindings.ReplaceKey (Key.D, Key.H);
         Assert.Empty (keyBindings.GetCommands (Key.D));
         Assert.Contains (Command.HotKey, keyBindings.GetCommands (Key.H));
     }
@@ -312,7 +312,7 @@ public class KeyBindingTests
     public void TryGet_WithCommands_ReturnsTrue ()
     {
         var keyBindings = new KeyBindings ();
-        keyBindings.Add (Key.A, Command.HotKey);
+        keyBindings.Add (Key.A, KeyBindingScope.Application, Command.HotKey);
         bool result = keyBindings.TryGet (Key.A, out KeyBinding bindings);
         Assert.True (result);
         Assert.Contains (Command.HotKey, bindings.Commands);
diff --git a/UnitTests/View/MouseTests.cs b/UnitTests/View/MouseTests.cs
index a0bef94f5..56548aff4 100644
--- a/UnitTests/View/MouseTests.cs
+++ b/UnitTests/View/MouseTests.cs
@@ -92,193 +92,7 @@ public class MouseTests (ITestOutputHelper output) : TestsAllViews
         view.NewMouseEvent (new MouseEvent () { Flags = mouseFlags });
         Assert.Equal (mouseFlagsFromEvent, expectedMouseFlagsFromEvent);
     }
-
-    [Theory]
-    [MemberData (nameof (AllViewTypes))]
-
-    public void AllViews_Enter_Leave_Events (Type viewType)
-    {
-        var view = CreateInstanceIfNotGeneric (viewType);
-
-        if (view == null)
-        {
-            output.WriteLine ($"Ignoring {viewType} - It's a Generic");
-            return;
-        }
-
-        if (!view.CanFocus)
-        {
-            output.WriteLine ($"Ignoring {viewType} - It can't focus.");
-
-            return;
-        }
-
-        if (view is Toplevel && ((Toplevel)view).Modal)
-        {
-            output.WriteLine ($"Ignoring {viewType} - It's a Modal Toplevel");
-
-            return;
-        }
-
-        Application.Init (new FakeDriver ());
-
-        Toplevel top = new ()
-        {
-            Height = 10,
-            Width = 10
-        };
-
-        View otherView = new ()
-        {
-            X = 0, Y = 0,
-            Height = 1,
-            Width = 1,
-            CanFocus = true,
-        };
-
-        view.X = Pos.Right (otherView);
-        view.Y = 0;
-        view.Width = 10;
-        view.Height = 1;
-
-        var nEnter = 0;
-        var nLeave = 0;
-
-        view.Enter += (s, e) => nEnter++;
-        view.Leave += (s, e) => nLeave++;
-
-        top.Add (view, otherView);
-        Application.Begin (top);
-
-        // Start with the focus on our test view
-        view.SetFocus ();
-
-        Assert.Equal (1, nEnter);
-        Assert.Equal (0, nLeave);
-
-        // Use keyboard to navigate to next view (otherView). 
-        if (view is TextView)
-        {
-            top.NewKeyDownEvent (Key.Tab.WithCtrl);
-        }
-        else if (view is DatePicker)
-        {
-            for (var i = 0; i < 4; i++)
-            {
-                top.NewKeyDownEvent (Key.Tab.WithCtrl);
-            }
-        }
-        else
-        {
-            top.NewKeyDownEvent (Key.Tab);
-        }
-
-        Assert.Equal (1, nEnter);
-        Assert.Equal (1, nLeave);
-
-        top.NewKeyDownEvent (Key.Tab);
-
-        Assert.Equal (2, nEnter);
-        Assert.Equal (1, nLeave);
-
-        top.Dispose ();
-        Application.Shutdown ();
-    }
-
-
-    [Theory]
-    [MemberData (nameof (AllViewTypes))]
-
-    public void AllViews_Enter_Leave_Events_Visible_False (Type viewType)
-    {
-        var view = CreateInstanceIfNotGeneric (viewType);
-
-        if (view == null)
-        {
-            output.WriteLine ($"Ignoring {viewType} - It's a Generic");
-            return;
-        }
-
-        if (!view.CanFocus)
-        {
-            output.WriteLine ($"Ignoring {viewType} - It can't focus.");
-
-            return;
-        }
-
-        if (view is Toplevel && ((Toplevel)view).Modal)
-        {
-            output.WriteLine ($"Ignoring {viewType} - It's a Modal Toplevel");
-
-            return;
-        }
-
-        Application.Init (new FakeDriver ());
-
-        Toplevel top = new ()
-        {
-            Height = 10,
-            Width = 10
-        };
-
-        View otherView = new ()
-        {
-            X = 0, Y = 0,
-            Height = 1,
-            Width = 1,
-            CanFocus = true,
-        };
-
-        view.Visible = false;
-        view.X = Pos.Right (otherView);
-        view.Y = 0;
-        view.Width = 10;
-        view.Height = 1;
-
-        var nEnter = 0;
-        var nLeave = 0;
-
-        view.Enter += (s, e) => nEnter++;
-        view.Leave += (s, e) => nLeave++;
-
-        top.Add (view, otherView);
-        Application.Begin (top);
-
-        // Start with the focus on our test view
-        view.SetFocus ();
-
-        Assert.Equal (0, nEnter);
-        Assert.Equal (0, nLeave);
-
-        // Use keyboard to navigate to next view (otherView). 
-        if (view is TextView)
-        {
-            top.NewKeyDownEvent (Key.Tab.WithCtrl);
-        }
-        else if (view is DatePicker)
-        {
-            for (var i = 0; i < 4; i++)
-            {
-                top.NewKeyDownEvent (Key.Tab.WithCtrl);
-            }
-        }
-        else
-        {
-            top.NewKeyDownEvent (Key.Tab);
-        }
-
-        Assert.Equal (0, nEnter);
-        Assert.Equal (0, nLeave);
-
-        top.NewKeyDownEvent (Key.Tab);
-
-        Assert.Equal (0, nEnter);
-        Assert.Equal (0, nLeave);
-
-        top.Dispose ();
-        Application.Shutdown ();
-    }
-
+    
     [Fact]
     public void NewMouseEvent_Invokes_MouseEvent_Properly ()
     {
diff --git a/UnitTests/View/NavigationTests.cs b/UnitTests/View/NavigationTests.cs
index 5a7019c19..1933c1662 100644
--- a/UnitTests/View/NavigationTests.cs
+++ b/UnitTests/View/NavigationTests.cs
@@ -2,7 +2,7 @@
 
 namespace Terminal.Gui.ViewTests;
 
-public class NavigationTests (ITestOutputHelper output)
+public class NavigationTests (ITestOutputHelper output) : TestsAllViews
 {
     [Fact]
     public void BringSubviewForward_Subviews_vs_TabIndexes ()
@@ -324,13 +324,13 @@ public class NavigationTests (ITestOutputHelper output)
         Assert.True (view2.CanFocus);
         Assert.False (view2.HasFocus); // Only one of the most focused toplevels view can have focus
 
-        Assert.True (top.NewKeyDownEvent (Key.Tab));
+        Assert.True (Application.OnKeyDown (Key.Tab));
         Assert.True (view1.CanFocus);
         Assert.False (view1.HasFocus); // Only one of the most focused toplevels view can have focus
         Assert.True (view2.CanFocus);
         Assert.True (view2.HasFocus);
 
-        Assert.True (top.NewKeyDownEvent (Key.Tab));
+        Assert.True (Application.OnKeyDown (Key.Tab));
         Assert.True (view1.CanFocus);
         Assert.True (view1.HasFocus);
         Assert.True (view2.CanFocus);
@@ -365,13 +365,13 @@ public class NavigationTests (ITestOutputHelper output)
         Assert.True (view2.CanFocus);
         Assert.False (view2.HasFocus); // Only one of the most focused toplevels view can have focus
 
-        Assert.True (top.NewKeyDownEvent (Key.Tab.WithCtrl));
+        Assert.True (Application.OnKeyDown (Key.Tab.WithCtrl));
         Assert.True (view1.CanFocus);
         Assert.False (view1.HasFocus); // Only one of the most focused toplevels view can have focus
         Assert.True (view2.CanFocus);
         Assert.True (view2.HasFocus);
 
-        Assert.True (top.NewKeyDownEvent (Key.Tab.WithCtrl));
+        Assert.True (Application.OnKeyDown (Key.Tab.WithCtrl));
         Assert.True (view1.CanFocus);
         Assert.True (view1.HasFocus);
         Assert.True (view2.CanFocus);
@@ -417,14 +417,14 @@ public class NavigationTests (ITestOutputHelper output)
         Assert.True (view2.CanFocus);
         Assert.False (view2.HasFocus); // Only one of the most focused toplevels view can have focus
 
-        Assert.True (top.NewKeyDownEvent (Key.Tab.WithCtrl));
-        Assert.True (top.NewKeyDownEvent (Key.Tab.WithCtrl));
+        Assert.True (Application.OnKeyDown (Key.Tab.WithCtrl));
+        Assert.True (Application.OnKeyDown (Key.Tab.WithCtrl));
         Assert.True (view1.CanFocus);
         Assert.False (view1.HasFocus); // Only one of the most focused toplevels view can have focus
         Assert.True (view2.CanFocus);
         Assert.True (view2.HasFocus);
 
-        Assert.True (top.NewKeyDownEvent (Key.Tab.WithCtrl));
+        Assert.True (Application.OnKeyDown (Key.Tab.WithCtrl));
         Assert.True (view1.CanFocus);
         Assert.True (view1.HasFocus);
         Assert.True (view2.CanFocus);
@@ -530,6 +530,7 @@ public class NavigationTests (ITestOutputHelper output)
     }
 
     [Fact]
+    [AutoInitShutdown]
     public void FocusNearestView_Ensure_Focus_Ordered ()
     {
         var top = new Toplevel ();
@@ -544,16 +545,17 @@ public class NavigationTests (ITestOutputHelper output)
         frm.Add (frmSubview);
         top.Add (frm);
 
-        top.NewKeyDownEvent (Key.Tab);
-        Assert.Equal ("WindowSubview", top.MostFocused.Text);
-        top.NewKeyDownEvent (Key.Tab);
-        Assert.Equal ("FrameSubview", top.MostFocused.Text);
-        top.NewKeyDownEvent (Key.Tab);
+        Application.Begin (top);
         Assert.Equal ("WindowSubview", top.MostFocused.Text);
 
-        top.NewKeyDownEvent (Key.Tab.WithShift);
+        Application.OnKeyDown (Key.Tab);
         Assert.Equal ("FrameSubview", top.MostFocused.Text);
-        top.NewKeyDownEvent (Key.Tab.WithShift);
+        Application.OnKeyDown (Key.Tab);
+        Assert.Equal ("WindowSubview", top.MostFocused.Text);
+
+        Application.OnKeyDown (Key.Tab.WithShift);
+        Assert.Equal ("FrameSubview", top.MostFocused.Text);
+        Application.OnKeyDown (Key.Tab.WithShift);
         Assert.Equal ("WindowSubview", top.MostFocused.Text);
         top.Dispose ();
     }
@@ -605,7 +607,7 @@ public class NavigationTests (ITestOutputHelper output)
         Assert.False (removed);
         Assert.Null (view3);
 
-        Assert.True (top1.NewKeyDownEvent (Key.Tab.WithCtrl));
+        Assert.True (Application.OnKeyDown (Key.Tab.WithCtrl));
         Assert.True (top1.HasFocus);
         Assert.False (view1.HasFocus);
         Assert.True (view2.HasFocus);
@@ -613,7 +615,7 @@ public class NavigationTests (ITestOutputHelper output)
         Assert.NotNull (view3);
 
         Exception exception =
-            Record.Exception (() => top1.NewKeyDownEvent (Key.Tab.WithCtrl));
+            Record.Exception (() => Application.OnKeyDown (Key.Tab.WithCtrl));
         Assert.Null (exception);
         Assert.True (removed);
         Assert.Null (view3);
@@ -1582,4 +1584,191 @@ public class NavigationTests (ITestOutputHelper output)
         Assert.True (view.HasFocus);
         Assert.Null (view.MostFocused); // BUGBUG: Should be view
     }
+
+
+    [Theory]
+    [MemberData (nameof (AllViewTypes))]
+
+    public void AllViews_Enter_Leave_Events (Type viewType)
+    {
+        var view = CreateInstanceIfNotGeneric (viewType);
+
+        if (view == null)
+        {
+            output.WriteLine ($"Ignoring {viewType} - It's a Generic");
+            return;
+        }
+
+        if (!view.CanFocus)
+        {
+            output.WriteLine ($"Ignoring {viewType} - It can't focus.");
+
+            return;
+        }
+
+        if (view is Toplevel && ((Toplevel)view).Modal)
+        {
+            output.WriteLine ($"Ignoring {viewType} - It's a Modal Toplevel");
+
+            return;
+        }
+
+        Application.Init (new FakeDriver ());
+
+        Toplevel top = new ()
+        {
+            Height = 10,
+            Width = 10
+        };
+
+        View otherView = new ()
+        {
+            X = 0, Y = 0,
+            Height = 1,
+            Width = 1,
+            CanFocus = true,
+        };
+
+        view.X = Pos.Right (otherView);
+        view.Y = 0;
+        view.Width = 10;
+        view.Height = 1;
+
+        var nEnter = 0;
+        var nLeave = 0;
+
+        view.Enter += (s, e) => nEnter++;
+        view.Leave += (s, e) => nLeave++;
+
+        top.Add (view, otherView);
+        Application.Begin (top);
+
+        // Start with the focus on our test view
+        view.SetFocus ();
+
+        Assert.Equal (1, nEnter);
+        Assert.Equal (0, nLeave);
+
+        // Use keyboard to navigate to next view (otherView). 
+        if (view is TextView)
+        {
+            Application.OnKeyDown (Key.Tab.WithCtrl);
+        }
+        else if (view is DatePicker)
+        {
+            for (var i = 0; i < 4; i++)
+            {
+                Application.OnKeyDown (Key.Tab.WithCtrl);
+            }
+        }
+        else
+        {
+            Application.OnKeyDown (Key.Tab);
+        }
+
+        Assert.Equal (1, nEnter);
+        Assert.Equal (1, nLeave);
+
+        Application.OnKeyDown (Key.Tab);
+
+        Assert.Equal (2, nEnter);
+        Assert.Equal (1, nLeave);
+
+        top.Dispose ();
+        Application.Shutdown ();
+    }
+
+
+    [Theory]
+    [MemberData (nameof (AllViewTypes))]
+
+    public void AllViews_Enter_Leave_Events_Visible_False (Type viewType)
+    {
+        var view = CreateInstanceIfNotGeneric (viewType);
+
+        if (view == null)
+        {
+            output.WriteLine ($"Ignoring {viewType} - It's a Generic");
+            return;
+        }
+
+        if (!view.CanFocus)
+        {
+            output.WriteLine ($"Ignoring {viewType} - It can't focus.");
+
+            return;
+        }
+
+        if (view is Toplevel && ((Toplevel)view).Modal)
+        {
+            output.WriteLine ($"Ignoring {viewType} - It's a Modal Toplevel");
+
+            return;
+        }
+
+        Application.Init (new FakeDriver ());
+
+        Toplevel top = new ()
+        {
+            Height = 10,
+            Width = 10
+        };
+
+        View otherView = new ()
+        {
+            X = 0, Y = 0,
+            Height = 1,
+            Width = 1,
+            CanFocus = true,
+        };
+
+        view.Visible = false;
+        view.X = Pos.Right (otherView);
+        view.Y = 0;
+        view.Width = 10;
+        view.Height = 1;
+
+        var nEnter = 0;
+        var nLeave = 0;
+
+        view.Enter += (s, e) => nEnter++;
+        view.Leave += (s, e) => nLeave++;
+
+        top.Add (view, otherView);
+        Application.Begin (top);
+
+        // Start with the focus on our test view
+        view.SetFocus ();
+
+        Assert.Equal (0, nEnter);
+        Assert.Equal (0, nLeave);
+
+        // Use keyboard to navigate to next view (otherView). 
+        if (view is TextView)
+        {
+            Application.OnKeyDown (Key.Tab.WithCtrl);
+        }
+        else if (view is DatePicker)
+        {
+            for (var i = 0; i < 4; i++)
+            {
+                Application.OnKeyDown (Key.Tab.WithCtrl);
+            }
+        }
+        else
+        {
+            Application.OnKeyDown (Key.Tab);
+        }
+
+        Assert.Equal (0, nEnter);
+        Assert.Equal (0, nLeave);
+
+        top.NewKeyDownEvent (Key.Tab);
+
+        Assert.Equal (0, nEnter);
+        Assert.Equal (0, nLeave);
+
+        top.Dispose ();
+        Application.Shutdown ();
+    }
 }
diff --git a/UnitTests/View/ViewKeyBindingTests.cs b/UnitTests/View/ViewKeyBindingTests.cs
index d10d8a0c0..2ac278a7b 100644
--- a/UnitTests/View/ViewKeyBindingTests.cs
+++ b/UnitTests/View/ViewKeyBindingTests.cs
@@ -19,7 +19,8 @@ public class ViewKeyBindingTests (ITestOutputHelper output)
         Application.Begin (top);
 
         Application.OnKeyDown (Key.A);
-        Assert.True (invoked);
+        Assert.False (invoked);
+        Assert.True (view.ApplicationCommand);
 
         invoked = false;
         Application.OnKeyDown (Key.H);
@@ -134,7 +135,7 @@ public class ViewKeyBindingTests (ITestOutputHelper output)
             AddCommand (Command.HotKey, () => HotKeyCommand = true);
             AddCommand (Command.Left, () => FocusedCommand = true);
 
-            KeyBindings.Add (Key.A, KeyBindingScope.Application, Command.Save);
+            Application.KeyBindings.Add (Key.A, this, Command.Save);
             HotKey = KeyCode.H;
             KeyBindings.Add (Key.F, KeyBindingScope.Focused, Command.Left);
         }
diff --git a/UnitTests/Views/AllViewsTests.cs b/UnitTests/Views/AllViewsTests.cs
index 92232d551..7b6945e7b 100644
--- a/UnitTests/Views/AllViewsTests.cs
+++ b/UnitTests/Views/AllViewsTests.cs
@@ -108,21 +108,21 @@ public class AllViewsTests (ITestOutputHelper output) : TestsAllViews
 
         if (vType is TextView)
         {
-            top.NewKeyDownEvent (Key.Tab.WithCtrl);
+            Application.OnKeyDown (Key.Tab.WithCtrl);
         }
         else if (vType is DatePicker)
         {
             for (var i = 0; i < 4; i++)
             {
-                top.NewKeyDownEvent (Key.Tab.WithCtrl);
+                Application.OnKeyDown (Key.Tab.WithCtrl);
             }
         }
         else
         {
-            top.NewKeyDownEvent (Key.Tab);
+            Application.OnKeyDown (Key.Tab);
         }
 
-        top.NewKeyDownEvent (Key.Tab);
+        Application.OnKeyDown (Key.Tab);
 
         Assert.Equal (2, vTypeEnter);
         Assert.Equal (1, vTypeLeave);
diff --git a/UnitTests/Views/OverlappedTests.cs b/UnitTests/Views/OverlappedTests.cs
index 5ca0fc566..2cf4fa96d 100644
--- a/UnitTests/Views/OverlappedTests.cs
+++ b/UnitTests/Views/OverlappedTests.cs
@@ -1030,28 +1030,30 @@ public class OverlappedTests
 
         var win1 = new Window { Id = "win1", Width = Dim.Percent (50), Height = Dim.Fill () };
         var lblTf1W1 = new Label { Text = "Enter text in TextField on Win1:" };
-        var tf1W1 = new TextField { X = Pos.Right (lblTf1W1) + 1, Width = Dim.Fill (), Text = "Text1 on Win1" };
+        var tf1W1 = new TextField { Id="tf1W1", X = Pos.Right (lblTf1W1) + 1, Width = Dim.Fill (), Text = "Text1 on Win1" };
         var lblTvW1 = new Label { Y = Pos.Bottom (lblTf1W1) + 1, Text = "Enter text in TextView on Win1:" };
 
         var tvW1 = new TextView
         {
+            Id = "tvW1",
             X = Pos.Left (tf1W1), Width = Dim.Fill (), Height = 2, Text = "First line Win1\nSecond line Win1"
         };
         var lblTf2W1 = new Label { Y = Pos.Bottom (lblTvW1) + 1, Text = "Enter text in TextField on Win1:" };
-        var tf2W1 = new TextField { X = Pos.Left (tf1W1), Width = Dim.Fill (), Text = "Text2 on Win1" };
+        var tf2W1 = new TextField { Id = "tf2W1", X = Pos.Left (tf1W1), Width = Dim.Fill (), Text = "Text2 on Win1" };
         win1.Add (lblTf1W1, tf1W1, lblTvW1, tvW1, lblTf2W1, tf2W1);
 
         var win2 = new Window { Id = "win2", Width = Dim.Percent (50), Height = Dim.Fill () };
         var lblTf1W2 = new Label { Text = "Enter text in TextField on Win2:" };
-        var tf1W2 = new TextField { X = Pos.Right (lblTf1W2) + 1, Width = Dim.Fill (), Text = "Text1 on Win2" };
+        var tf1W2 = new TextField { Id = "tf1W2", X = Pos.Right (lblTf1W2) + 1, Width = Dim.Fill (), Text = "Text1 on Win2" };
         var lblTvW2 = new Label { Y = Pos.Bottom (lblTf1W2) + 1, Text = "Enter text in TextView on Win2:" };
 
         var tvW2 = new TextView
         {
+            Id = "tvW2",
             X = Pos.Left (tf1W2), Width = Dim.Fill (), Height = 2, Text = "First line Win1\nSecond line Win2"
         };
         var lblTf2W2 = new Label { Y = Pos.Bottom (lblTvW2) + 1, Text = "Enter text in TextField on Win2:" };
-        var tf2W2 = new TextField { X = Pos.Left (tf1W2), Width = Dim.Fill (), Text = "Text2 on Win2" };
+        var tf2W2 = new TextField { Id = "tf2W2", X = Pos.Left (tf1W2), Width = Dim.Fill (), Text = "Text2 on Win2" };
         win2.Add (lblTf1W2, tf1W2, lblTvW2, tvW2, lblTf2W2, tf2W2);
 
         win1.Closing += (s, e) => isRunning = false;
@@ -1104,72 +1106,69 @@ public class OverlappedTests
         Assert.True (Application.OnKeyDown (Key.Tab));
         Assert.Equal ($"\tFirst line Win1{Environment.NewLine}Second line Win1", tvW1.Text);
 
-        Assert.True (
-                     Application.OnKeyDown (Key.Tab.WithShift)
-                    );
+        Assert.True (Application.OnKeyDown (Key.Tab.WithShift));
         Assert.Equal ($"First line Win1{Environment.NewLine}Second line Win1", tvW1.Text);
 
-        Assert.True (
-                     Application.OnKeyDown (Key.Tab.WithCtrl)
-                    );
+        Assert.True (Application.OnKeyDown (Key.Tab.WithCtrl));    // move to win2
+        Assert.Equal (win2, Application.OverlappedChildren [0]);
+
+        Assert.True (Application.OnKeyDown (Key.Tab.WithCtrl.WithShift));    // move back to win1
         Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf2W1, win1.MostFocused);
-        Assert.True (Application.OnKeyDown (Key.Tab));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf1W1, win1.MostFocused);
-        Assert.True (Application.OnKeyDown (Key.CursorRight));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf1W1, win1.MostFocused);
-        Assert.True (Application.OnKeyDown (Key.CursorDown));
+
+        Assert.Equal (tvW1, win1.MostFocused);
+        Assert.True (Application.OnKeyDown (Key.Tab));    // text view eats tab
         Assert.Equal (win1, Application.OverlappedChildren [0]);
         Assert.Equal (tvW1, win1.MostFocused);
+
+        tvW1.AllowsTab = false;
+        Assert.True (Application.OnKeyDown (Key.Tab));    // text view eats tab
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tf2W1, win1.MostFocused);
+
+        Assert.True (Application.OnKeyDown (Key.CursorRight));
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tf2W1, win1.MostFocused);
+        Assert.True (Application.OnKeyDown (Key.CursorDown));
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tf1W1, win1.MostFocused);
 #if UNIX_KEY_BINDINGS
         Assert.True (Application.OverlappedChildren [0].ProcessKeyDown (new (Key.I.WithCtrl)));
         Assert.Equal (win1, Application.OverlappedChildren [0]);
         Assert.Equal (tf2W1, win1.MostFocused);
 #endif
-        Assert.True (
-                     Application.OverlappedChildren [0]
-                                .NewKeyDownEvent (Key.Tab.WithShift)
-                    );
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tvW1, win1.MostFocused);
-        Assert.True (Application.OnKeyDown (Key.CursorLeft));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf1W1, win1.MostFocused);
-        Assert.True (Application.OnKeyDown (Key.CursorUp));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf2W1, win1.MostFocused);
         Assert.True (Application.OnKeyDown (Key.Tab));
         Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf1W1, win1.MostFocused);
+        Assert.Equal (tvW1, win1.MostFocused);
+        Assert.True (Application.OnKeyDown (Key.CursorLeft));  // The view to the left of tvW1 is tf2W1, but tvW1 is still focused and eats cursor keys
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tvW1, win1.MostFocused);
+        Assert.True (Application.OnKeyDown (Key.CursorUp));
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tvW1, win1.MostFocused);
+        Assert.True (Application.OnKeyDown (Key.Tab));
+        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (tf2W1, win1.MostFocused);
 
-        Assert.True (
-                     Application.OverlappedChildren [0]
-                                .NewKeyDownEvent (Key.Tab.WithCtrl)
-                    );
+        Assert.True (Application.OnKeyDown (Key.Tab.WithCtrl)); // Move to win2
         Assert.Equal (win2, Application.OverlappedChildren [0]);
         Assert.Equal (tf1W2, win2.MostFocused);
         tf2W2.SetFocus ();
         Assert.True (tf2W2.HasFocus);
 
-        Assert.True (
-                     Application.OverlappedChildren [0]
-                                .NewKeyDownEvent (Key.Tab.WithCtrl.WithShift)
-                    );
+        Assert.True (Application.OnKeyDown (Key.Tab.WithCtrl.WithShift));
         Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf1W1, win1.MostFocused);
+        Assert.Equal (tf2W1, win1.MostFocused);
         Assert.True (Application.OnKeyDown (Application.AlternateForwardKey));
         Assert.Equal (win2, Application.OverlappedChildren [0]);
         Assert.Equal (tf2W2, win2.MostFocused);
         Assert.True (Application.OnKeyDown (Application.AlternateBackwardKey));
         Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf1W1, win1.MostFocused);
+        Assert.Equal (tf2W1, win1.MostFocused);
         Assert.True (Application.OnKeyDown (Key.CursorDown));
         Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tvW1, win1.MostFocused);
+        Assert.Equal (tf1W1, win1.MostFocused);
 #if UNIX_KEY_BINDINGS
-        Assert.True (Application.OverlappedChildren [0].ProcessKeyDown (new (Key.B.WithCtrl)));
+        Assert.True (Application.OnKeyDown (new (Key.B.WithCtrl)));
 #else
         Assert.True (Application.OnKeyDown (Key.CursorLeft));
 #endif
@@ -1180,20 +1179,17 @@ public class OverlappedTests
         Assert.Equal (tvW1, win1.MostFocused);
         Assert.Equal (Point.Empty, tvW1.CursorPosition);
 
-        Assert.True (
-                     Application.OverlappedChildren [0]
-                                .NewKeyDownEvent (Key.End.WithCtrl)
-                    );
+        Assert.True (Application.OnKeyDown (Key.End.WithCtrl));
         Assert.Equal (win1, Application.OverlappedChildren [0]);
         Assert.Equal (tvW1, win1.MostFocused);
         Assert.Equal (new (16, 1), tvW1.CursorPosition);
 #if UNIX_KEY_BINDINGS
-        Assert.True (Application.OverlappedChildren [0].ProcessKeyDown (new (Key.F.WithCtrl)));
+        Assert.True (Application.OnKeyDown (new (Key.F.WithCtrl)));
 #else
         Assert.True (Application.OnKeyDown (Key.CursorRight));
 #endif
         Assert.Equal (win1, Application.OverlappedChildren [0]);
-        Assert.Equal (tf2W1, win1.MostFocused);
+        Assert.Equal (tvW1, win1.MostFocused);
 
 #if UNIX_KEY_BINDINGS
         Assert.True (Application.OverlappedChildren [0].ProcessKeyDown (new (Key.L.WithCtrl)));
diff --git a/UnitTests/Views/TableViewTests.cs b/UnitTests/Views/TableViewTests.cs
index 6740120f6..a87bb533e 100644
--- a/UnitTests/Views/TableViewTests.cs
+++ b/UnitTests/Views/TableViewTests.cs
@@ -2993,7 +2993,7 @@ A B C
         dt.Rows.Add (1, 2, 3, 4, 5, 6);
 
         tableView.MultiSelect = true;
-        tableView.KeyBindings.Add (Key.Space, Command.Select);
+        tableView.KeyBindings.ReplaceCommands (Key.Space, Command.Select);
 
         Point selectedCell = tableView.GetAllSelectedCells ().Single ();
         Assert.Equal (0, selectedCell.X);
@@ -3065,7 +3065,7 @@ A B C
         dt.Rows.Add (1, 2, 3, 4, 5, 6);
         tableView.FullRowSelect = true;
         tableView.MultiSelect = true;
-        tableView.KeyBindings.Add (Key.Space, Command.Select);
+        tableView.KeyBindings.ReplaceCommands (Key.Space, Command.Select);
 
         // Toggle Select Cell 0,0
         tableView.NewKeyDownEvent (new() { KeyCode = KeyCode.Space });
@@ -3101,7 +3101,7 @@ A B C
         dt.Rows.Add (1, 2, 3, 4, 5, 6);
         dt.Rows.Add (1, 2, 3, 4, 5, 6);
         tableView.MultiSelect = true;
-        tableView.KeyBindings.Add (Key.Space, Command.Select);
+        tableView.KeyBindings.ReplaceCommands (Key.Space, Command.Select);
 
         // Make a square selection
         tableView.NewKeyDownEvent (new() { KeyCode = KeyCode.ShiftMask | KeyCode.CursorDown });
@@ -3142,7 +3142,7 @@ A B C
         dt.Rows.Add (1, 2, 3, 4, 5, 6);
         dt.Rows.Add (1, 2, 3, 4, 5, 6);
         tableView.MultiSelect = true;
-        tableView.KeyBindings.Add (Key.Space, Command.Select);
+        tableView.KeyBindings.ReplaceCommands (Key.Space, Command.Select);
 
         // Make first square selection (0,0 to 1,1)
         tableView.NewKeyDownEvent (new() { KeyCode = KeyCode.ShiftMask | KeyCode.CursorDown });
diff --git a/UnitTests/Views/ToplevelTests.cs b/UnitTests/Views/ToplevelTests.cs
index c19c72bb1..7a5f9700c 100644
--- a/UnitTests/Views/ToplevelTests.cs
+++ b/UnitTests/Views/ToplevelTests.cs
@@ -485,27 +485,31 @@ public partial class ToplevelTests (ITestOutputHelper output)
         Assert.Equal ($"First line Win1{Environment.NewLine}Second line Win1", tvW1.Text);
         Assert.True (Application.OnKeyDown (Key.Tab.WithCtrl));
         Assert.Equal (win1, top.Focused);
-        Assert.Equal (tf2W1, top.MostFocused);
+        Assert.Equal (tf2W1, top.MostFocused); // tf2W1 is last subview in win1 - tabbing should take us to first subview of win2
         Assert.True (Application.OnKeyDown (Key.Tab));
-        Assert.Equal (win1, top.Focused);
-        Assert.Equal (tf1W1, top.MostFocused);
-        Assert.True (Application.OnKeyDown (Key.CursorRight));
-        Assert.Equal (win1, top.Focused);
-        Assert.Equal (tf1W1, top.MostFocused);
-        Assert.True (Application.OnKeyDown (Key.CursorDown));
-        Assert.Equal (win1, top.Focused);
-        Assert.Equal (tvW1, top.MostFocused);
+        Assert.Equal (win2, top.Focused);
+        Assert.Equal (tf1W2, top.MostFocused);
+        Assert.True (Application.OnKeyDown (Key.CursorRight)); // move char to right in tf1W2
+        Assert.Equal (win2, top.Focused);
+        Assert.Equal (tf1W2, top.MostFocused);   
+        Assert.True (Application.OnKeyDown (Key.CursorDown)); // move down to next view (tvW2)
+        Assert.Equal (win2, top.Focused);
+        Assert.Equal (tvW2, top.MostFocused);
 #if UNIX_KEY_BINDINGS
         Assert.True (Application.OnKeyDown (new (Key.I.WithCtrl)));
         Assert.Equal (win1, top.Focused);
         Assert.Equal (tf2W1, top.MostFocused);
 #endif
-        Assert.True (Application.OnKeyDown (Key.Tab.WithShift));
-        Assert.Equal (win1, top.Focused);
-        Assert.Equal (tvW1, top.MostFocused);
+        Assert.True (Application.OnKeyDown (Key.Tab.WithShift)); // Ignored. TextView eats shift-tab by default
+        Assert.Equal (win2, top.Focused);
+        Assert.Equal (tvW2, top.MostFocused);
+        tvW2.AllowsTab = false;
+        Assert.True (Application.OnKeyDown (Key.Tab.WithShift)); 
+        Assert.Equal (win2, top.Focused);
+        Assert.Equal (tf1W2, top.MostFocused);
         Assert.True (Application.OnKeyDown (Key.CursorLeft));
-        Assert.Equal (win1, top.Focused);
-        Assert.Equal (tf1W1, top.MostFocused);
+        Assert.Equal (win2, top.Focused);
+        Assert.Equal (tf1W2, top.MostFocused);
         Assert.True (Application.OnKeyDown (Key.CursorUp));
         Assert.Equal (win1, top.Focused);
         Assert.Equal (tf2W1, top.MostFocused);
diff --git a/UnitTests/Views/TreeTableSourceTests.cs b/UnitTests/Views/TreeTableSourceTests.cs
index 39e18327b..a1a319b1b 100644
--- a/UnitTests/Views/TreeTableSourceTests.cs
+++ b/UnitTests/Views/TreeTableSourceTests.cs
@@ -187,7 +187,7 @@ public class TreeTableSourceTests : IDisposable
         Assert.Equal (0, tv.SelectedRow);
         Assert.Equal (1, tv.SelectedColumn);
 
-        top.NewKeyDownEvent (Key.CursorRight);
+        Application.OnKeyDown (Key.CursorRight);
 
         tv.Draw ();
 

From 22dcbc1a782539e5ee423ef66e0bd9ee5ab6cf62 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Wed, 24 Jul 2024 12:36:45 -0600
Subject: [PATCH 14/33] removed un needed key handling code from TextView

---
 .../Application/Application.Keyboard.cs       | 12 ++--
 Terminal.Gui/Views/TextView.cs                | 58 +------------------
 2 files changed, 11 insertions(+), 59 deletions(-)

diff --git a/Terminal.Gui/Application/Application.Keyboard.cs b/Terminal.Gui/Application/Application.Keyboard.cs
index c725b13bd..84fade3cb 100644
--- a/Terminal.Gui/Application/Application.Keyboard.cs
+++ b/Terminal.Gui/Application/Application.Keyboard.cs
@@ -358,9 +358,10 @@ public static partial class Application // Keyboard handling
                    );
 
         AddCommand (
-                    Command.NextView,    // TODO: Figure out how to move this to the View that is at the root of the view hierarchy (currently Application.Top)
+                    Command.NextView,    
                     () =>
                     {
+                        // TODO: Move this method to Application.Navigation.cs
                         Current.MoveNextView ();
 
                         return true;
@@ -368,9 +369,10 @@ public static partial class Application // Keyboard handling
                    );
 
         AddCommand (
-                    Command.PreviousView,// TODO: Figure out how to move this to the View that is at the root of the view hierarchy (currently Application.Top)
+                    Command.PreviousView,
                     () =>
                     {
+                        // TODO: Move this method to Application.Navigation.cs
                         Current.MovePreviousView ();
 
                         return true;
@@ -378,9 +380,10 @@ public static partial class Application // Keyboard handling
                    );
 
         AddCommand (
-                    Command.NextViewOrTop,// TODO: Figure out how to move this to the View that is at the root of the view hierarchy (currently Application.Top)
+                    Command.NextViewOrTop,
                     () =>
                     {
+                        // TODO: Move this method to Application.Navigation.cs
                         Current.MoveNextViewOrTop ();
 
                         return true;
@@ -388,9 +391,10 @@ public static partial class Application // Keyboard handling
                    );
 
         AddCommand (
-                    Command.PreviousViewOrTop,// TODO: Figure out how to move this to the View that is at the root of the view hierarchy (currently Application.Top)
+                    Command.PreviousViewOrTop,
                     () =>
                     {
+                        // TODO: Move this method to Application.Navigation.cs
                         Current.MovePreviousViewOrTop ();
 
                         return true;
diff --git a/Terminal.Gui/Views/TextView.cs b/Terminal.Gui/Views/TextView.cs
index 598f78961..db8627b47 100644
--- a/Terminal.Gui/Views/TextView.cs
+++ b/Terminal.Gui/Views/TextView.cs
@@ -2369,8 +2369,6 @@ public class TextView : View
                    );
         AddCommand (Command.Tab, () => ProcessTab ());
         AddCommand (Command.BackTab, () => ProcessBackTab ());
-        //AddCommand (Command.NextView, () => ProcessMoveNextView ());
-        //AddCommand (Command.PreviousView, () => ProcessMovePreviousView ());
 
         AddCommand (
                     Command.Undo,
@@ -2503,12 +2501,6 @@ public class TextView : View
         KeyBindings.Add (Key.Tab, Command.Tab);
         KeyBindings.Add (Key.Tab.WithShift, Command.BackTab);
 
-        //KeyBindings.Add (Key.Tab.WithCtrl, Command.NextView);
-        //KeyBindings.Add (Application.AlternateForwardKey, Command.NextView);
-
-        //KeyBindings.Add (Key.Tab.WithCtrl.WithShift, Command.PreviousView);
-        //KeyBindings.Add (Application.AlternateBackwardKey, Command.PreviousView);
-
         KeyBindings.Add (Key.Z.WithCtrl, Command.Undo);
         KeyBindings.Add (Key.R.WithCtrl, Command.Redo);
 
@@ -5365,16 +5357,6 @@ public class TextView : View
         DoNeededAction ();
     }
 
-    private bool MoveNextView ()
-    {
-        if (Application.OverlappedTop is { })
-        {
-            return SuperView?.FocusNext () == true;
-        }
-
-        return false;
-    }
-
     private void MovePageDown ()
     {
         int nPageDnShift = Viewport.Height - 1;
@@ -5431,16 +5413,6 @@ public class TextView : View
         DoNeededAction ();
     }
 
-    private bool MovePreviousView ()
-    {
-        if (Application.OverlappedTop is { })
-        {
-            return SuperView?.FocusPrev () == true;
-        }
-
-        return false;
-    }
-
     private void MoveRight ()
     {
         List<RuneCell> currentLine = GetCurrentLine ();
@@ -5617,7 +5589,7 @@ public class TextView : View
 
         if (!AllowsTab || _isReadOnly)
         {
-            return ProcessMovePreviousView ();
+            return false;
         }
 
         if (CurrentColumn > 0)
@@ -5889,21 +5861,7 @@ public class TextView : View
         StartSelecting ();
         MoveLeft ();
     }
-
-    private bool ProcessMoveNextView ()
-    {
-        ResetColumnTrack ();
-
-        return MoveNextView ();
-    }
-
-    private bool ProcessMovePreviousView ()
-    {
-        ResetColumnTrack ();
-
-        return MovePreviousView ();
-    }
-
+    
     private bool ProcessMoveRight ()
     {
         // if the user presses Right (without any control keys)
@@ -6163,7 +6121,7 @@ public class TextView : View
 
         if (!AllowsTab || _isReadOnly)
         {
-            return ProcessMoveNextView ();
+            return false;
         }
 
         InsertText (new Key ((KeyCode)'\t'));
@@ -6369,13 +6327,6 @@ public class TextView : View
     private void TextView_Initialized (object sender, EventArgs e)
     {
         Autocomplete.HostControl = this;
-
-        if (Application.Top is { })
-        {
-            Application.Top.AlternateForwardKeyChanged += Top_AlternateForwardKeyChanged!;
-            Application.Top.AlternateBackwardKeyChanged += Top_AlternateBackwardKeyChanged!;
-        }
-
         OnContentsChanged ();
     }
 
@@ -6393,9 +6344,6 @@ public class TextView : View
         _selectionStartRow = CurrentRow;
     }
 
-    private void Top_AlternateBackwardKeyChanged (object sender, KeyChangedEventArgs e) { KeyBindings.ReplaceKey (e.OldKey, e.NewKey); }
-    private void Top_AlternateForwardKeyChanged (object sender, KeyChangedEventArgs e) { KeyBindings.ReplaceKey (e.OldKey, e.NewKey); }
-
     // Tries to snap the cursor to the tracking column
     private void TrackColumn ()
     {

From c088f2e98cfbad285a7291f9db5eec429ce87d84 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Wed, 24 Jul 2024 12:38:59 -0600
Subject: [PATCH 15/33] removed unneeded key handling code from Toplevel

---
 Terminal.Gui/Views/Toplevel.cs | 125 ---------------------------------
 1 file changed, 125 deletions(-)

diff --git a/Terminal.Gui/Views/Toplevel.cs b/Terminal.Gui/Views/Toplevel.cs
index fb31efb73..4c23b215f 100644
--- a/Terminal.Gui/Views/Toplevel.cs
+++ b/Terminal.Gui/Views/Toplevel.cs
@@ -31,15 +31,10 @@ public partial class Toplevel : View
         Arrangement = ViewArrangement.Fixed;
         Width = Dim.Fill ();
         Height = Dim.Fill ();
-
         ColorScheme = Colors.ColorSchemes ["TopLevel"];
-
-        //ConfigureKeyBindings ();
-
         MouseClick += Toplevel_MouseClick;
     }
 
-
     #region Keyboard & Mouse
 
     // TODO: IRunnable: Re-implement - Modal means IRunnable, ViewArrangement.Overlapped where modalView.Z > allOtherViews.Max (v = v.Z), and exclusive key/mouse input.
@@ -65,114 +60,6 @@ public partial class Toplevel : View
     /// </summary>
     public bool Modal { get; set; }
 
-    // TODO: Overlapped: Figure out how these keybindings should work.
-    private void ConfigureKeyBindings ()
-    {
-        // Things this view knows how to do
-        AddCommand (
-                    Command.QuitToplevel,  // TODO: IRunnable: Rename to Command.Quit to make more generic.
-                    () =>
-                    {
-                        QuitToplevel ();
-
-                        return true;
-                    }
-                   );
-
-        /// TODO: Overlapped: Add Command.ShowHide
-
-        AddCommand (
-                    Command.Suspend,    // TODO: Move to Application
-                    () =>
-                    {
-                        Driver.Suspend ();
-                        ;
-
-                        return true;
-                    }
-                   );
-
-        AddCommand (
-                    Command.NextView,    // TODO: Figure out how to move this to the View that is at the root of the view hierarchy (currently Application.Top)
-                    () =>
-                    {
-                        MoveNextView ();
-
-                        return true;
-                    }
-                   );
-
-        AddCommand (
-                    Command.PreviousView,// TODO: Figure out how to move this to the View that is at the root of the view hierarchy (currently Application.Top)
-                    () =>
-                    {
-                        MovePreviousView ();
-
-                        return true;
-                    }
-                   );
-
-        AddCommand (
-                    Command.NextViewOrTop,// TODO: Figure out how to move this to the View that is at the root of the view hierarchy (currently Application.Top)
-                    () =>
-                    {
-                        MoveNextViewOrTop ();
-
-                        return true;
-                    }
-                   );
-
-        AddCommand (
-                    Command.PreviousViewOrTop,// TODO: Figure out how to move this to the View that is at the root of the view hierarchy (currently Application.Top)
-                    () =>
-                    {
-                        MovePreviousViewOrTop ();
-
-                        return true;
-                    }
-                   );
-
-        AddCommand (
-                    Command.Refresh,
-                    () =>
-                    {
-                        Application.Refresh (); // TODO: Move to Application
-
-                        return true;
-                    }
-                   );
-
-        // Default keybindings for this view
-        KeyBindings.Add (Application.QuitKey, Command.QuitToplevel);
-
-        KeyBindings.Add (Key.CursorRight, Command.NextView);
-        KeyBindings.Add (Key.CursorDown, Command.NextView);
-        KeyBindings.Add (Key.CursorLeft, Command.PreviousView);
-        KeyBindings.Add (Key.CursorUp, Command.PreviousView);
-
-        KeyBindings.Add (Key.Tab, Command.NextView);
-        KeyBindings.Add (Key.Tab.WithShift, Command.PreviousView);
-        KeyBindings.Add (Key.Tab.WithCtrl, Command.NextViewOrTop);
-        KeyBindings.Add (Key.Tab.WithShift.WithCtrl, Command.PreviousViewOrTop);
-
-        // TODO: Refresh Key should be configurable
-        KeyBindings.Add (Key.F5, KeyBindingScope.Application, Command.Refresh);
-        KeyBindings.Add (Application.AlternateForwardKey, Command.NextViewOrTop); // Needed on Unix
-        KeyBindings.Add (Application.AlternateBackwardKey, Command.PreviousViewOrTop); // Needed on Unix
-
-        if (Environment.OSVersion.Platform == PlatformID.Unix)
-        {
-            KeyBindings.Add (Key.Z.WithCtrl, Command.Suspend);
-        }
-
-#if UNIX_KEY_BINDINGS
-        KeyBindings.Add (Key.L.WithCtrl, Command.Refresh); // Unix
-        KeyBindings.Add (Key.F.WithCtrl, Command.NextView); // Unix
-        KeyBindings.Add (Key.I.WithCtrl, Command.NextView); // Unix
-        KeyBindings.Add (Key.B.WithCtrl, Command.PreviousView); // Unix
-#endif
-    }
-
     private void Toplevel_MouseClick (object sender, MouseEventEventArgs e) { e.Handled = InvokeCommand (Command.HotKey) == true; }
 
     // TODO: Deprecate - No need for this at View level; having at Application is sufficient.
@@ -500,18 +387,6 @@ public partial class Toplevel : View
         Unloaded?.Invoke (this, EventArgs.Empty);
     }
 
-    private void QuitToplevel ()
-    {
-        if (Application.OverlappedTop is { })
-        {
-            RequestStop (this);
-        }
-        else
-        {
-            Application.RequestStop ();
-        }
-    }
-
     #endregion
 
     #region Draw

From 4a56b84324a67fb990aa781ac82212c1574597e2 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Wed, 24 Jul 2024 12:41:28 -0600
Subject: [PATCH 16/33] removed unneeded AlternateBack/FormardKey code from
 Toplevel

---
 .../Application/Application.Keyboard.cs       | 32 --------
 Terminal.Gui/Views/Toplevel.cs                | 37 ---------
 UnitTests/Views/ToplevelTests.cs              | 76 +------------------
 3 files changed, 1 insertion(+), 144 deletions(-)

diff --git a/Terminal.Gui/Application/Application.Keyboard.cs b/Terminal.Gui/Application/Application.Keyboard.cs
index 84fade3cb..c05ba6c34 100644
--- a/Terminal.Gui/Application/Application.Keyboard.cs
+++ b/Terminal.Gui/Application/Application.Keyboard.cs
@@ -29,20 +29,10 @@ public static partial class Application // Keyboard handling
                 {
                     KeyBindings.ReplaceKey (oldKey, _alternateForwardKey);
                 }
-                OnAlternateForwardKeyChanged (new (oldKey, value));
             }
         }
     }
 
-    private static void OnAlternateForwardKeyChanged (KeyChangedEventArgs e)
-    {
-        // TODO: The fact Top has it's own AlternateForwardKey and events is needlessly complex. Remove it.
-        foreach (Toplevel top in _topLevels.ToArray ())
-        {
-            top.OnAlternateForwardKeyChanged (e);
-        }
-    }
-
     private static Key _alternateBackwardKey = Key.Empty; // Defined in config.json
 
     /// <summary>Alternative key to navigate backwards through views. Shift+Ctrl+Tab is the primary key.</summary>
@@ -66,21 +56,10 @@ public static partial class Application // Keyboard handling
                 {
                     KeyBindings.ReplaceKey (oldKey, _alternateBackwardKey);
                 }
-
-                OnAlternateBackwardKeyChanged (new (oldKey, value));
             }
         }
     }
 
-    private static void OnAlternateBackwardKeyChanged (KeyChangedEventArgs oldKey)
-    {
-        // TODO: The fact Top has it's own AlternateBackwardKey and events is needlessly complex. Remove it.
-        foreach (Toplevel top in _topLevels.ToArray ())
-        {
-            top.OnAlternateBackwardKeyChanged (oldKey);
-        }
-    }
-
     private static Key _quitKey = Key.Empty; // Defined in config.json
 
     /// <summary>Gets or sets the key to quit the application.</summary>
@@ -103,21 +82,10 @@ public static partial class Application // Keyboard handling
                 {
                     KeyBindings.ReplaceKey (oldKey, _quitKey);
                 }
-                OnQuitKeyChanged (new (oldKey, value));
             }
         }
     }
 
-    private static void OnQuitKeyChanged (KeyChangedEventArgs e)
-    {
-        // TODO: The fact Top has it's own QuitKey and events is needlessly complex. Remove it.
-        // Duplicate the list so if it changes during enumeration we're safe
-        foreach (Toplevel top in _topLevels.ToArray ())
-        {
-            top.OnQuitKeyChanged (e);
-        }
-    }
-
     /// <summary>
     ///     Event fired when the user presses a key. Fired by <see cref="OnKeyDown"/>.
     ///     <para>
diff --git a/Terminal.Gui/Views/Toplevel.cs b/Terminal.Gui/Views/Toplevel.cs
index 4c23b215f..3a862bd69 100644
--- a/Terminal.Gui/Views/Toplevel.cs
+++ b/Terminal.Gui/Views/Toplevel.cs
@@ -62,43 +62,6 @@ public partial class Toplevel : View
 
     private void Toplevel_MouseClick (object sender, MouseEventEventArgs e) { e.Handled = InvokeCommand (Command.HotKey) == true; }
 
-    // TODO: Deprecate - No need for this at View level; having at Application is sufficient.
-    /// <summary>Invoked when the <see cref="Application.AlternateBackwardKey"/> is changed.</summary>
-    public event EventHandler<KeyChangedEventArgs> AlternateBackwardKeyChanged;
-
-    // TODO: Deprecate - No need for this at View level; having at Application is sufficient.
-    /// <summary>Invoked when the <see cref="Application.AlternateForwardKey"/> is changed.</summary>
-    public event EventHandler<KeyChangedEventArgs> AlternateForwardKeyChanged;
-
-    // TODO: Deprecate - No need for this at View level; having at Application is sufficient.
-    /// <summary>Virtual method to invoke the <see cref="AlternateBackwardKeyChanged"/> event.</summary>
-    /// <param name="e"></param>
-    public virtual void OnAlternateBackwardKeyChanged (KeyChangedEventArgs e)
-    {
-        KeyBindings.ReplaceKey (e.OldKey, e.NewKey);
-        AlternateBackwardKeyChanged?.Invoke (this, e);
-    }
-
-    // TODO: Deprecate - No need for this at View level; having at Application is sufficient.
-    /// <summary>Virtual method to invoke the <see cref="AlternateForwardKeyChanged"/> event.</summary>
-    /// <param name="e"></param>
-    public virtual void OnAlternateForwardKeyChanged (KeyChangedEventArgs e)
-    {
-        KeyBindings.ReplaceKey (e.OldKey, e.NewKey);
-        AlternateForwardKeyChanged?.Invoke (this, e);
-    }
-
-    /// <summary>Virtual method to invoke the <see cref="QuitKeyChanged"/> event.</summary>
-    /// <param name="e"></param>
-    public virtual void OnQuitKeyChanged (KeyChangedEventArgs e)
-    {
-        KeyBindings.ReplaceKey (e.OldKey, e.NewKey);
-        QuitKeyChanged?.Invoke (this, e);
-    }
-
-    /// <summary>Invoked when the <see cref="Application.QuitKey"/> is changed.</summary>
-    public event EventHandler<KeyChangedEventArgs> QuitKeyChanged;
-
     #endregion
 
     #region Subviews
diff --git a/UnitTests/Views/ToplevelTests.cs b/UnitTests/Views/ToplevelTests.cs
index 7a5f9700c..2d4a0a323 100644
--- a/UnitTests/Views/ToplevelTests.cs
+++ b/UnitTests/Views/ToplevelTests.cs
@@ -573,23 +573,6 @@ public partial class ToplevelTests (ITestOutputHelper output)
 
         void View_Added (object sender, SuperViewChangedEventArgs e)
         {
-            Assert.Throws<NullReferenceException> (
-                                                   () =>
-                                                       Application.Top.AlternateForwardKeyChanged +=
-                                                           (s, e) => alternateForwardKey = (KeyCode)e.OldKey
-                                                  );
-
-            Assert.Throws<NullReferenceException> (
-                                                   () =>
-                                                       Application.Top.AlternateBackwardKeyChanged +=
-                                                           (s, e) => alternateBackwardKey = (KeyCode)e.OldKey
-                                                  );
-
-            Assert.Throws<NullReferenceException> (
-                                                   () =>
-                                                       Application.Top.QuitKeyChanged += (s, e) =>
-                                                                                             quitKey = (KeyCode)e.OldKey
-                                                  );
             Assert.False (wasAdded);
             wasAdded = true;
             view.Added -= View_Added;
@@ -605,64 +588,7 @@ public partial class ToplevelTests (ITestOutputHelper output)
 
         Application.Shutdown ();
     }
-
-    [Fact]
-    [AutoInitShutdown]
-    public void AlternateForwardKeyChanged_AlternateBackwardKeyChanged_QuitKeyChanged_Events ()
-    {
-        Key alternateForwardKey = KeyCode.Null;
-        Key alternateBackwardKey = KeyCode.Null;
-        Key quitKey = KeyCode.Null;
-
-        Key previousQuitKey = Application.QuitKey;
-
-        Toplevel top = new ();
-        var view = new View ();
-        view.Initialized += View_Initialized;
-
-        void View_Initialized (object sender, EventArgs e)
-        {
-            top.AlternateForwardKeyChanged += (s, e) => alternateForwardKey = e.OldKey;
-            top.AlternateBackwardKeyChanged += (s, e) => alternateBackwardKey = e.OldKey;
-            top.QuitKeyChanged += (s, e) => quitKey = e.OldKey;
-        }
-
-        var win = new Window ();
-        win.Add (view);
-        top.Add (win);
-        Application.Begin (top);
-
-        Assert.Equal (KeyCode.Null, alternateForwardKey);
-        Assert.Equal (KeyCode.Null, alternateBackwardKey);
-        Assert.Equal (KeyCode.Null, quitKey);
-
-        Assert.Equal (KeyCode.PageDown | KeyCode.CtrlMask, Application.AlternateForwardKey);
-        Assert.Equal (KeyCode.PageUp | KeyCode.CtrlMask, Application.AlternateBackwardKey);
-        Assert.Equal (Key.Esc, Application.QuitKey);
-
-        Application.AlternateForwardKey = KeyCode.A;
-        Application.AlternateBackwardKey = KeyCode.B;
-        Application.QuitKey = KeyCode.C;
-
-        Assert.Equal (KeyCode.PageDown | KeyCode.CtrlMask, alternateForwardKey);
-        Assert.Equal (KeyCode.PageUp | KeyCode.CtrlMask, alternateBackwardKey);
-        Assert.Equal (previousQuitKey, quitKey);
-
-        Assert.Equal (KeyCode.A, Application.AlternateForwardKey);
-        Assert.Equal (KeyCode.B, Application.AlternateBackwardKey);
-        Assert.Equal (KeyCode.C, Application.QuitKey);
-
-        // Replacing the defaults keys to avoid errors on others unit tests that are using it.
-        Application.AlternateForwardKey = Key.PageDown.WithCtrl;
-        Application.AlternateBackwardKey = Key.PageUp.WithCtrl;
-        Application.QuitKey = previousQuitKey;
-
-        Assert.Equal (KeyCode.PageDown | KeyCode.CtrlMask, Application.AlternateForwardKey);
-        Assert.Equal (KeyCode.PageUp | KeyCode.CtrlMask, Application.AlternateBackwardKey);
-        Assert.Equal (previousQuitKey, Application.QuitKey);
-        top.Dispose ();
-    }
-
+    
     [Fact]
     [AutoInitShutdown]
     public void Mouse_Drag_On_Top_With_Superview_Null ()

From 0c56dfeb5a5d2e995291a717f4ee451552736be4 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Wed, 24 Jul 2024 12:56:55 -0600
Subject: [PATCH 17/33] Moved view navigation out of Toplevel and into
 Application (via ViewNavigation static class).

---
 .../Application/Application.Keyboard.cs       |   8 +-
 .../Application/Application.Overlapped.cs     | 163 ++++++++++++++++++
 Terminal.Gui/Input/KeyBindings.cs             |  19 ++
 Terminal.Gui/Views/Toplevel.cs                | 160 +----------------
 4 files changed, 187 insertions(+), 163 deletions(-)

diff --git a/Terminal.Gui/Application/Application.Keyboard.cs b/Terminal.Gui/Application/Application.Keyboard.cs
index c05ba6c34..bc6507c86 100644
--- a/Terminal.Gui/Application/Application.Keyboard.cs
+++ b/Terminal.Gui/Application/Application.Keyboard.cs
@@ -330,7 +330,7 @@ public static partial class Application // Keyboard handling
                     () =>
                     {
                         // TODO: Move this method to Application.Navigation.cs
-                        Current.MoveNextView ();
+                        ViewNavigation.MoveNextView ();
 
                         return true;
                     }
@@ -341,7 +341,7 @@ public static partial class Application // Keyboard handling
                     () =>
                     {
                         // TODO: Move this method to Application.Navigation.cs
-                        Current.MovePreviousView ();
+                        ViewNavigation.MovePreviousView ();
 
                         return true;
                     }
@@ -352,7 +352,7 @@ public static partial class Application // Keyboard handling
                     () =>
                     {
                         // TODO: Move this method to Application.Navigation.cs
-                        Current.MoveNextViewOrTop ();
+                        ViewNavigation.MoveNextViewOrTop ();
 
                         return true;
                     }
@@ -363,7 +363,7 @@ public static partial class Application // Keyboard handling
                     () =>
                     {
                         // TODO: Move this method to Application.Navigation.cs
-                        Current.MovePreviousViewOrTop ();
+                        ViewNavigation.MovePreviousViewOrTop ();
 
                         return true;
                     }
diff --git a/Terminal.Gui/Application/Application.Overlapped.cs b/Terminal.Gui/Application/Application.Overlapped.cs
index 58eccfa3a..1ac547fde 100644
--- a/Terminal.Gui/Application/Application.Overlapped.cs
+++ b/Terminal.Gui/Application/Application.Overlapped.cs
@@ -1,6 +1,169 @@
 #nullable enable
+using static Terminal.Gui.View;
+using System.Reflection;
+
 namespace Terminal.Gui;
 
+internal static class ViewNavigation
+{
+    /// <summary>
+    ///    Gets the deepest focused subview of the specified <paramref name="view"/>.
+    /// </summary>
+    /// <param name="view"></param>
+    /// <returns></returns>
+    internal static View GetDeepestFocusedSubview (View view)
+    {
+        if (view is null)
+        {
+            return null;
+        }
+
+        foreach (View v in view.Subviews)
+        {
+            if (v.HasFocus)
+            {
+                return GetDeepestFocusedSubview (v);
+            }
+        }
+
+        return view;
+    }
+
+    /// <summary>
+    ///    Sets the focus to the next view in the <see cref="TabIndexes"/> list. If the last view is focused, the first view is focused.
+    /// </summary>
+    /// <param name="viewsInTabIndexes"></param>
+    /// <param name="direction"></param>
+    internal static void FocusNearestView (IEnumerable<View>? viewsInTabIndexes, NavigationDirection direction)
+    {
+        if (viewsInTabIndexes is null)
+        {
+            return;
+        }
+
+        var found = false;
+        var focusProcessed = false;
+        var idx = 0;
+
+        foreach (View v in viewsInTabIndexes)
+        {
+            if (v == Application.Current)
+            {
+                found = true;
+            }
+
+            if (found && v != Application.Current)
+            {
+                if (direction == NavigationDirection.Forward)
+                {
+                    Application.Current.SuperView?.FocusNext ();
+                }
+                else
+                {
+                    Application.Current.SuperView?.FocusPrev ();
+                }
+
+                focusProcessed = true;
+
+                if (Application.Current.SuperView?.Focused is { } && Application.Current.SuperView.Focused != Application.Current)
+                {
+                    return;
+                }
+            }
+            else if (found && !focusProcessed && idx == viewsInTabIndexes.Count () - 1)
+            {
+                viewsInTabIndexes.ToList () [0].SetFocus ();
+            }
+
+            idx++;
+        }
+    }
+    /// <summary>
+    ///     Moves the focus to 
+    /// </summary>
+    internal static void MoveNextView ()
+    {
+        View old = GetDeepestFocusedSubview (Application.Current.Focused);
+
+        if (!Application.Current.FocusNext ())
+        {
+            Application.Current.FocusNext ();
+        }
+
+        if (old != Application.Current.Focused && old != Application.Current.Focused?.Focused)
+        {
+            old?.SetNeedsDisplay ();
+            Application.Current.Focused?.SetNeedsDisplay ();
+        }
+        else
+        {
+            FocusNearestView (Application.Current.SuperView?.TabIndexes, NavigationDirection.Forward);
+        }
+    }
+
+    internal static void MoveNextViewOrTop ()
+    {
+        if (Application.OverlappedTop is null)
+        {
+            Toplevel top = Application.Current.Modal ? Application.Current : Application.Top;
+            top.FocusNext ();
+
+            if (top.Focused is null)
+            {
+                top.FocusNext ();
+            }
+
+            top.SetNeedsDisplay ();
+            Application.BringOverlappedTopToFront ();
+        }
+        else
+        {
+            Application.OverlappedMoveNext ();
+        }
+    }
+
+    internal static void MovePreviousView ()
+    {
+        View old = GetDeepestFocusedSubview (Application.Current.Focused);
+
+        if (!Application.Current.FocusPrev ())
+        {
+            Application.Current.FocusPrev ();
+        }
+
+        if (old != Application.Current.Focused && old != Application.Current.Focused?.Focused)
+        {
+            old?.SetNeedsDisplay ();
+            Application.Current.Focused?.SetNeedsDisplay ();
+        }
+        else
+        {
+            FocusNearestView (Application.Current.SuperView?.TabIndexes?.Reverse (), NavigationDirection.Backward);
+        }
+    }
+
+    internal static void MovePreviousViewOrTop ()
+    {
+        if (Application.OverlappedTop is null)
+        {
+            Toplevel top = Application.Current.Modal ? Application.Current : Application.Top;
+            top.FocusPrev ();
+
+            if (top.Focused is null)
+            {
+                top.FocusPrev ();
+            }
+
+            top.SetNeedsDisplay ();
+            Application.BringOverlappedTopToFront ();
+        }
+        else
+        {
+            Application.OverlappedMovePrevious ();
+        }
+    }
+}
+
 public static partial class Application // App-level View Navigation
 {
  
diff --git a/Terminal.Gui/Input/KeyBindings.cs b/Terminal.Gui/Input/KeyBindings.cs
index 8ca45568e..89ffde7ad 100644
--- a/Terminal.Gui/Input/KeyBindings.cs
+++ b/Terminal.Gui/Input/KeyBindings.cs
@@ -110,6 +110,25 @@ public class KeyBindings
         }
     }
 
+
+    /// <summary>
+    ///     <para>Adds a new key combination that will trigger the commands in <paramref name="commands"/>.</para>
+    ///     <para>
+    ///         If the key is already bound to a different array of <see cref="Command"/>s it will be rebound
+    ///         <paramref name="commands"/>.
+    ///     </para>
+    /// </summary>
+    /// <remarks>
+    ///     Commands are only ever applied to the current <see cref="View"/> (i.e. this feature cannot be used to switch
+    ///     focus to another view and perform multiple commands there).
+    /// </remarks>
+    /// <param name="key">The key to check.</param>
+    /// <param name="scope">The scope for the command.</param>
+    /// <param name="commands">
+    ///     The command to invoked on the <see cref="View"/> when <paramref name="key"/> is pressed. When
+    ///     multiple commands are provided,they will be applied in sequence. The bound <paramref name="key"/> strike will be
+    ///     consumed if any took effect.
+    /// </param>
     public void Add (Key key, KeyBindingScope scope,  params Command [] commands)
     {
         if (BoundView is { } && scope.FastHasFlags (KeyBindingScope.Application))
diff --git a/Terminal.Gui/Views/Toplevel.cs b/Terminal.Gui/Views/Toplevel.cs
index 3a862bd69..11d216210 100644
--- a/Terminal.Gui/Views/Toplevel.cs
+++ b/Terminal.Gui/Views/Toplevel.cs
@@ -411,165 +411,7 @@ public partial class Toplevel : View
 
     /// <inheritdoc/>
     public override bool OnLeave (View view) { return MostFocused?.OnLeave (view) ?? base.OnLeave (view); }
-
-    /// <summary>
-    ///    Sets the focus to the next view in the <see cref="TabIndexes"/> list. If the last view is focused, the first view is focused.
-    /// </summary>
-    /// <param name="viewsInTabIndexes"></param>
-    /// <param name="direction"></param>
-    private void FocusNearestView (IEnumerable<View> viewsInTabIndexes, NavigationDirection direction)
-    {
-        if (viewsInTabIndexes is null)
-        {
-            return;
-        }
-
-        var found = false;
-        var focusProcessed = false;
-        var idx = 0;
-
-        foreach (View v in viewsInTabIndexes)
-        {
-            if (v == this)
-            {
-                found = true;
-            }
-
-            if (found && v != this)
-            {
-                if (direction == NavigationDirection.Forward)
-                {
-                    SuperView?.FocusNext ();
-                }
-                else
-                {
-                    SuperView?.FocusPrev ();
-                }
-
-                focusProcessed = true;
-
-                if (SuperView.Focused is { } && SuperView.Focused != this)
-                {
-                    return;
-                }
-            }
-            else if (found && !focusProcessed && idx == viewsInTabIndexes.Count () - 1)
-            {
-                viewsInTabIndexes.ToList () [0].SetFocus ();
-            }
-
-            idx++;
-        }
-    }
-
-    /// <summary>
-    ///    Gets the deepest focused subview of the specified <paramref name="view"/>.
-    /// </summary>
-    /// <param name="view"></param>
-    /// <returns></returns>
-    private View GetDeepestFocusedSubview (View view)
-    {
-        if (view is null)
-        {
-            return null;
-        }
-
-        foreach (View v in view.Subviews)
-        {
-            if (v.HasFocus)
-            {
-                return GetDeepestFocusedSubview (v);
-            }
-        }
-
-        return view;
-    }
-
-    /// <summary>
-    ///     Moves the focus to 
-    /// </summary>
-    internal void MoveNextView ()
-    {
-        View old = GetDeepestFocusedSubview (Focused);
-
-        if (!FocusNext ())
-        {
-            FocusNext ();
-        }
-
-        if (old != Focused && old != Focused?.Focused)
-        {
-            old?.SetNeedsDisplay ();
-            Focused?.SetNeedsDisplay ();
-        }
-        else
-        {
-            FocusNearestView (SuperView?.TabIndexes, NavigationDirection.Forward);
-        }
-    }
-
-    internal void MoveNextViewOrTop ()
-    {
-        if (Application.OverlappedTop is null)
-        {
-            Toplevel top = Modal ? this : Application.Top;
-            top.FocusNext ();
-
-            if (top.Focused is null)
-            {
-                top.FocusNext ();
-            }
-
-            top.SetNeedsDisplay ();
-            Application.BringOverlappedTopToFront ();
-        }
-        else
-        {
-            Application.OverlappedMoveNext ();
-        }
-    }
-
-    internal void MovePreviousView ()
-    {
-        View old = GetDeepestFocusedSubview (Focused);
-
-        if (!FocusPrev ())
-        {
-            FocusPrev ();
-        }
-
-        if (old != Focused && old != Focused?.Focused)
-        {
-            old?.SetNeedsDisplay ();
-            Focused?.SetNeedsDisplay ();
-        }
-        else
-        {
-            FocusNearestView (SuperView?.TabIndexes?.Reverse (), NavigationDirection.Backward);
-        }
-    }
-
-    internal void MovePreviousViewOrTop ()
-    {
-        if (Application.OverlappedTop is null)
-        {
-            Toplevel top = Modal ? this : Application.Top;
-            top.FocusPrev ();
-
-            if (top.Focused is null)
-            {
-                top.FocusPrev ();
-            }
-
-            top.SetNeedsDisplay ();
-            Application.BringOverlappedTopToFront ();
-        }
-        else
-        {
-            Application.OverlappedMovePrevious ();
-        }
-    }
-
+    
     #endregion
 
     #region Size / Position Management

From 73a9dc37c48587e4d042ada19ece2296b17b0fe5 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Wed, 24 Jul 2024 14:15:32 -0600
Subject: [PATCH 18/33] Fixed nullable warnings 2

---
 .../Application/Application.Initialization.cs |  32 ++--
 .../Application/Application.Keyboard.cs       |   6 +-
 Terminal.Gui/Application/Application.Mouse.cs |  14 +-
 .../Application/Application.Overlapped.cs     |  20 +--
 Terminal.Gui/Application/Application.Run.cs   |  74 +++++----
 .../Application/Application.Toplevel.cs       |   6 +-
 Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs  |   5 +-
 Terminal.Gui/View/Adornment/Margin.cs         |   4 +-
 Terminal.Gui/View/Adornment/ShadowView.cs     |   2 +-
 Terminal.Gui/View/Layout/Dim.cs               |   2 +-
 Terminal.Gui/View/Layout/DimView.cs           |   2 +-
 Terminal.Gui/View/Layout/Pos.cs               |   4 +-
 Terminal.Gui/View/Layout/PosView.cs           |   2 +-
 Terminal.Gui/Views/Menu/MenuBar.cs            |   2 +-
 UICatalog/UICatalog.cs                        |   2 +-
 UnitTests/Views/MenuBarTests.cs               | 142 ++++++++----------
 UnitTests/Views/ToplevelTests.cs              |   9 +-
 17 files changed, 154 insertions(+), 174 deletions(-)

diff --git a/Terminal.Gui/Application/Application.Initialization.cs b/Terminal.Gui/Application/Application.Initialization.cs
index 2e184b285..0d9b2caf5 100644
--- a/Terminal.Gui/Application/Application.Initialization.cs
+++ b/Terminal.Gui/Application/Application.Initialization.cs
@@ -36,7 +36,7 @@ public static partial class Application // Initialization (Init/Shutdown)
     /// </param>
     [RequiresUnreferencedCode ("AOT")]
     [RequiresDynamicCode ("AOT")]
-    public static void Init (ConsoleDriver driver = null, string driverName = null) { InternalInit (driver, driverName); }
+    public static void Init (ConsoleDriver? driver = null, string? driverName = null) { InternalInit (driver, driverName); }
 
     internal static bool _initialized;
     internal static int _mainThreadId = -1;
@@ -53,8 +53,8 @@ public static partial class Application // Initialization (Init/Shutdown)
     [RequiresUnreferencedCode ("AOT")]
     [RequiresDynamicCode ("AOT")]
     internal static void InternalInit (
-        ConsoleDriver driver = null,
-        string driverName = null,
+        ConsoleDriver? driver = null,
+        string? driverName = null,
         bool calledViaRunT = false
     )
     {
@@ -114,17 +114,17 @@ public static partial class Application // Initialization (Init/Shutdown)
             }
             else
             {
-                List<Type> drivers = GetDriverTypes ();
-                Type driverType = drivers.FirstOrDefault (t => t.Name.Equals (ForceDriver, StringComparison.InvariantCultureIgnoreCase));
+                List<Type?> drivers = GetDriverTypes ();
+                Type? driverType = drivers.FirstOrDefault (t => t!.Name.Equals (ForceDriver, StringComparison.InvariantCultureIgnoreCase));
 
                 if (driverType is { })
                 {
-                    Driver = (ConsoleDriver)Activator.CreateInstance (driverType);
+                    Driver = (ConsoleDriver)Activator.CreateInstance (driverType)!;
                 }
                 else
                 {
                     throw new ArgumentException (
-                                                 $"Invalid driver name: {ForceDriver}. Valid names are {string.Join (", ", drivers.Select (t => t.Name))}"
+                                                 $"Invalid driver name: {ForceDriver}. Valid names are {string.Join (", ", drivers.Select (t => t!.Name))}"
                                                 );
                 }
             }
@@ -132,7 +132,7 @@ public static partial class Application // Initialization (Init/Shutdown)
 
         try
         {
-            MainLoop = Driver.Init ();
+            MainLoop = Driver!.Init ();
         }
         catch (InvalidOperationException ex)
         {
@@ -159,22 +159,22 @@ public static partial class Application // Initialization (Init/Shutdown)
         InitializedChanged?.Invoke (null, new (in _initialized));
     }
 
-    private static void Driver_SizeChanged (object sender, SizeChangedEventArgs e) { OnSizeChanging (e); }
-    private static void Driver_KeyDown (object sender, Key e) { OnKeyDown (e); }
-    private static void Driver_KeyUp (object sender, Key e) { OnKeyUp (e); }
-    private static void Driver_MouseEvent (object sender, MouseEvent e) { OnMouseEvent (e); }
+    private static void Driver_SizeChanged (object? sender, SizeChangedEventArgs e) { OnSizeChanging (e); }
+    private static void Driver_KeyDown (object? sender, Key e) { OnKeyDown (e); }
+    private static void Driver_KeyUp (object? sender, Key e) { OnKeyUp (e); }
+    private static void Driver_MouseEvent (object? sender, MouseEvent e) { OnMouseEvent (e); }
 
     /// <summary>Gets of list of <see cref="ConsoleDriver"/> types that are available.</summary>
     /// <returns></returns>
     [RequiresUnreferencedCode ("AOT")]
-    public static List<Type> GetDriverTypes ()
+    public static List<Type?> GetDriverTypes ()
     {
         // use reflection to get the list of drivers
-        List<Type> driverTypes = new ();
+        List<Type?> driverTypes = new ();
 
         foreach (Assembly asm in AppDomain.CurrentDomain.GetAssemblies ())
         {
-            foreach (Type type in asm.GetTypes ())
+            foreach (Type? type in asm.GetTypes ())
             {
                 if (type.IsSubclassOf (typeof (ConsoleDriver)) && !type.IsAbstract)
                 {
@@ -207,5 +207,5 @@ public static partial class Application // Initialization (Init/Shutdown)
     /// <remarks>
     ///     Intended to support unit tests that need to know when the application has been initialized.
     /// </remarks>
-    public static event EventHandler<EventArgs<bool>> InitializedChanged;
+    public static event EventHandler<EventArgs<bool>>? InitializedChanged;
 }
diff --git a/Terminal.Gui/Application/Application.Keyboard.cs b/Terminal.Gui/Application/Application.Keyboard.cs
index bc6507c86..10419bf80 100644
--- a/Terminal.Gui/Application/Application.Keyboard.cs
+++ b/Terminal.Gui/Application/Application.Keyboard.cs
@@ -98,7 +98,7 @@ public static partial class Application // Keyboard handling
     ///     <see cref="KeyDown"/> and <see cref="KeyUp"/> events.
     ///     <para>Fired after <see cref="KeyDown"/> and before <see cref="KeyUp"/>.</para>
     /// </remarks>
-    public static event EventHandler<Key> KeyDown;
+    public static event EventHandler<Key>? KeyDown;
 
     /// <summary>
     ///     Called by the <see cref="ConsoleDriver"/> when the user presses a key. Fires the <see cref="KeyDown"/> event
@@ -199,7 +199,7 @@ public static partial class Application // Keyboard handling
     ///     <see cref="KeyDown"/> and <see cref="KeyUp"/> events.
     ///     <para>Fired after <see cref="KeyDown"/>.</para>
     /// </remarks>
-    public static event EventHandler<Key> KeyUp;
+    public static event EventHandler<Key>? KeyUp;
 
     /// <summary>
     ///     Called by the <see cref="ConsoleDriver"/> when the user releases a key. Fires the <see cref="KeyUp"/> event
@@ -304,7 +304,7 @@ public static partial class Application // Keyboard handling
                     {
                         if (OverlappedTop is { })
                         {
-                            RequestStop (Current);
+                            RequestStop (Current!);
                         }
                         else
                         {
diff --git a/Terminal.Gui/Application/Application.Mouse.cs b/Terminal.Gui/Application/Application.Mouse.cs
index 61fc6d63e..713e6375d 100644
--- a/Terminal.Gui/Application/Application.Mouse.cs
+++ b/Terminal.Gui/Application/Application.Mouse.cs
@@ -9,32 +9,32 @@ public static partial class Application // Mouse handling
     public static bool IsMouseDisabled { get; set; }
 
     /// <summary>The current <see cref="View"/> object that wants continuous mouse button pressed events.</summary>
-    public static View WantContinuousButtonPressedView { get; private set; }
+    public static View? WantContinuousButtonPressedView { get; private set; }
 
     /// <summary>
     ///     Gets the view that grabbed the mouse (e.g. for dragging). When this is set, all mouse events will be routed to
     ///     this view until the view calls <see cref="UngrabMouse"/> or the mouse is released.
     /// </summary>
-    public static View MouseGrabView { get; private set; }
+    public static View? MouseGrabView { get; private set; }
 
     /// <summary>Invoked when a view wants to grab the mouse; can be canceled.</summary>
-    public static event EventHandler<GrabMouseEventArgs> GrabbingMouse;
+    public static event EventHandler<GrabMouseEventArgs>? GrabbingMouse;
 
     /// <summary>Invoked when a view wants un-grab the mouse; can be canceled.</summary>
-    public static event EventHandler<GrabMouseEventArgs> UnGrabbingMouse;
+    public static event EventHandler<GrabMouseEventArgs>? UnGrabbingMouse;
 
     /// <summary>Invoked after a view has grabbed the mouse.</summary>
-    public static event EventHandler<ViewEventArgs> GrabbedMouse;
+    public static event EventHandler<ViewEventArgs>? GrabbedMouse;
 
     /// <summary>Invoked after a view has un-grabbed the mouse.</summary>
-    public static event EventHandler<ViewEventArgs> UnGrabbedMouse;
+    public static event EventHandler<ViewEventArgs>? UnGrabbedMouse;
 
     /// <summary>
     ///     Grabs the mouse, forcing all mouse events to be routed to the specified view until <see cref="UngrabMouse"/>
     ///     is called.
     /// </summary>
     /// <param name="view">View that will receive all mouse events until <see cref="UngrabMouse"/> is invoked.</param>
-    public static void GrabMouse (View view)
+    public static void GrabMouse (View? view)
     {
         if (view is null)
         {
diff --git a/Terminal.Gui/Application/Application.Overlapped.cs b/Terminal.Gui/Application/Application.Overlapped.cs
index 1ac547fde..26e931c98 100644
--- a/Terminal.Gui/Application/Application.Overlapped.cs
+++ b/Terminal.Gui/Application/Application.Overlapped.cs
@@ -11,7 +11,7 @@ internal static class ViewNavigation
     /// </summary>
     /// <param name="view"></param>
     /// <returns></returns>
-    internal static View GetDeepestFocusedSubview (View view)
+    internal static View? GetDeepestFocusedSubview (View? view)
     {
         if (view is null)
         {
@@ -30,7 +30,7 @@ internal static class ViewNavigation
     }
 
     /// <summary>
-    ///    Sets the focus to the next view in the <see cref="TabIndexes"/> list. If the last view is focused, the first view is focused.
+    ///    Sets the focus to the next view in the <see cref="View.TabIndexes"/> list. If the last view is focused, the first view is focused.
     /// </summary>
     /// <param name="viewsInTabIndexes"></param>
     /// <param name="direction"></param>
@@ -56,11 +56,11 @@ internal static class ViewNavigation
             {
                 if (direction == NavigationDirection.Forward)
                 {
-                    Application.Current.SuperView?.FocusNext ();
+                    Application.Current!.SuperView?.FocusNext ();
                 }
                 else
                 {
-                    Application.Current.SuperView?.FocusPrev ();
+                    Application.Current!.SuperView?.FocusPrev ();
                 }
 
                 focusProcessed = true;
@@ -83,7 +83,7 @@ internal static class ViewNavigation
     /// </summary>
     internal static void MoveNextView ()
     {
-        View old = GetDeepestFocusedSubview (Application.Current.Focused);
+        View? old = GetDeepestFocusedSubview (Application.Current!.Focused);
 
         if (!Application.Current.FocusNext ())
         {
@@ -105,8 +105,8 @@ internal static class ViewNavigation
     {
         if (Application.OverlappedTop is null)
         {
-            Toplevel top = Application.Current.Modal ? Application.Current : Application.Top;
-            top.FocusNext ();
+            Toplevel? top = Application.Current!.Modal ? Application.Current : Application.Top;
+            top!.FocusNext ();
 
             if (top.Focused is null)
             {
@@ -124,7 +124,7 @@ internal static class ViewNavigation
 
     internal static void MovePreviousView ()
     {
-        View old = GetDeepestFocusedSubview (Application.Current.Focused);
+        View? old = GetDeepestFocusedSubview (Application.Current!.Focused);
 
         if (!Application.Current.FocusPrev ())
         {
@@ -146,8 +146,8 @@ internal static class ViewNavigation
     {
         if (Application.OverlappedTop is null)
         {
-            Toplevel top = Application.Current.Modal ? Application.Current : Application.Top;
-            top.FocusPrev ();
+            Toplevel? top = Application.Current!.Modal ? Application.Current : Application.Top;
+            top!.FocusPrev ();
 
             if (top.Focused is null)
             {
diff --git a/Terminal.Gui/Application/Application.Run.cs b/Terminal.Gui/Application/Application.Run.cs
index 541ad7141..bbff9c1ba 100644
--- a/Terminal.Gui/Application/Application.Run.cs
+++ b/Terminal.Gui/Application/Application.Run.cs
@@ -8,7 +8,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
 {
     // When `End ()` is called, it is possible `RunState.Toplevel` is a different object than `Top`.
     // This variable is set in `End` in this case so that `Begin` correctly sets `Top`.
-    private static Toplevel _cachedRunStateToplevel;
+    private static Toplevel? _cachedRunStateToplevel;
 
     /// <summary>
     ///     Notify that a new <see cref="RunState"/> was created (<see cref="Begin(Toplevel)"/> was called). The token is
@@ -19,7 +19,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
     ///     must also subscribe to <see cref="NotifyStopRunState"/> and manually dispose of the <see cref="RunState"/> token
     ///     when the application is done.
     /// </remarks>
-    public static event EventHandler<RunStateEventArgs> NotifyNewRunState;
+    public static event EventHandler<RunStateEventArgs>? NotifyNewRunState;
 
     /// <summary>Notify that an existent <see cref="RunState"/> is stopping (<see cref="End(RunState)"/> was called).</summary>
     /// <remarks>
@@ -27,7 +27,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
     ///     must also subscribe to <see cref="NotifyStopRunState"/> and manually dispose of the <see cref="RunState"/> token
     ///     when the application is done.
     /// </remarks>
-    public static event EventHandler<ToplevelEventArgs> NotifyStopRunState;
+    public static event EventHandler<ToplevelEventArgs>? NotifyStopRunState;
 
     /// <summary>Building block API: Prepares the provided <see cref="Toplevel"/> for execution.</summary>
     /// <returns>
@@ -96,9 +96,9 @@ public static partial class Application // Run (Begin, Run, End, Stop)
                     throw new ObjectDisposedException (Top.GetType ().FullName);
                 }
             }
-            else if (OverlappedTop is { } && toplevel != Top && _topLevels.Contains (Top))
+            else if (OverlappedTop is { } && toplevel != Top && _topLevels.Contains (Top!))
             {
-                Top.OnLeave (toplevel);
+                Top!.OnLeave (toplevel);
             }
 
             // BUGBUG: We should not depend on `Id` internally.
@@ -120,7 +120,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             }
             else
             {
-                Toplevel dup = _topLevels.FirstOrDefault (x => x.Id == toplevel.Id);
+                Toplevel? dup = _topLevels.FirstOrDefault (x => x.Id == toplevel.Id);
 
                 if (dup is null)
                 {
@@ -150,7 +150,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             if (toplevel.Visible)
             {
                 Current?.OnDeactivate (toplevel);
-                Toplevel previousCurrent = Current;
+                Toplevel previousCurrent = Current!;
                 Current = toplevel;
                 Current.OnActivate (previousCurrent);
 
@@ -161,11 +161,10 @@ public static partial class Application // Run (Begin, Run, End, Stop)
                 refreshDriver = false;
             }
         }
-        else if ((OverlappedTop != null
-                  && toplevel != OverlappedTop
+        else if ((toplevel != OverlappedTop
                   && Current?.Modal == true
                   && !_topLevels.Peek ().Modal)
-                 || (OverlappedTop is { } && toplevel != OverlappedTop && Current?.Running == false))
+                 || (toplevel != OverlappedTop && Current?.Running == false))
         {
             refreshDriver = false;
             MoveCurrent (toplevel);
@@ -173,10 +172,10 @@ public static partial class Application // Run (Begin, Run, End, Stop)
         else
         {
             refreshDriver = false;
-            MoveCurrent (Current);
+            MoveCurrent (Current!);
         }
 
-        toplevel.SetRelativeLayout (Driver.Screen.Size);
+        toplevel.SetRelativeLayout (Driver!.Screen.Size);
 
         toplevel.LayoutSubviews ();
         toplevel.PositionToplevels ();
@@ -216,7 +215,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
     internal static bool PositionCursor (View view)
     {
         // Find the most focused view and position the cursor there.
-        View mostFocused = view?.MostFocused;
+        View? mostFocused = view?.MostFocused;
 
         if (mostFocused is null)
         {
@@ -233,7 +232,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
         // If the view is not visible or enabled, don't position the cursor
         if (!mostFocused.Visible || !mostFocused.Enabled)
         {
-            Driver.GetCursorVisibility (out CursorVisibility current);
+            Driver!.GetCursorVisibility (out CursorVisibility current);
 
             if (current != CursorVisibility.Invisible)
             {
@@ -245,7 +244,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
 
         // If the view is not visible within it's superview, don't position the cursor
         Rectangle mostFocusedViewport = mostFocused.ViewportToScreen (mostFocused.Viewport with { Location = Point.Empty });
-        Rectangle superViewViewport = mostFocused.SuperView?.ViewportToScreen (mostFocused.SuperView.Viewport with { Location = Point.Empty }) ?? Driver.Screen;
+        Rectangle superViewViewport = mostFocused.SuperView?.ViewportToScreen (mostFocused.SuperView.Viewport with { Location = Point.Empty }) ?? Driver!.Screen;
 
         if (!superViewViewport.IntersectsWith (mostFocusedViewport))
         {
@@ -254,7 +253,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
 
         Point? cursor = mostFocused.PositionCursor ();
 
-        Driver.GetCursorVisibility (out CursorVisibility currentCursorVisibility);
+        Driver!.GetCursorVisibility (out CursorVisibility currentCursorVisibility);
 
         if (cursor is { })
         {
@@ -306,7 +305,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
     /// <returns>The created <see cref="Toplevel"/> object. The caller is responsible for disposing this object.</returns>
     [RequiresUnreferencedCode ("AOT")]
     [RequiresDynamicCode ("AOT")]
-    public static Toplevel Run (Func<Exception, bool> errorHandler = null, ConsoleDriver driver = null) { return Run<Toplevel> (errorHandler, driver); }
+    public static Toplevel Run (Func<Exception, bool>? errorHandler = null, ConsoleDriver? driver = null) { return Run<Toplevel> (errorHandler, driver); }
 
     /// <summary>
     ///     Runs the application by creating a <see cref="Toplevel"/>-derived object of type <c>T</c> and calling
@@ -331,7 +330,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
     /// <returns>The created T object. The caller is responsible for disposing this object.</returns>
     [RequiresUnreferencedCode ("AOT")]
     [RequiresDynamicCode ("AOT")]
-    public static T Run<T> (Func<Exception, bool> errorHandler = null, ConsoleDriver driver = null)
+    public static T Run<T> (Func<Exception, bool>? errorHandler = null, ConsoleDriver? driver = null)
         where T : Toplevel, new ()
     {
         if (!_initialized)
@@ -385,7 +384,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
     ///     RELEASE builds only: Handler for any unhandled exceptions (resumes when returns true,
     ///     rethrows when null).
     /// </param>
-    public static void Run (Toplevel view, Func<Exception, bool> errorHandler = null)
+    public static void Run (Toplevel view, Func<Exception, bool>? errorHandler = null)
     {
         ArgumentNullException.ThrowIfNull (view);
 
@@ -460,7 +459,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
     ///     reset, repeating the invocation. If it returns false, the timeout will stop and be removed. The returned value is a
     ///     token that can be used to stop the timeout by calling <see cref="RemoveTimeout(object)"/>.
     /// </remarks>
-    public static object AddTimeout (TimeSpan time, Func<bool> callback) { return MainLoop?.AddTimeout (time, callback); }
+    public static object AddTimeout (TimeSpan time, Func<bool> callback) { return MainLoop!.AddTimeout (time, callback); }
 
     /// <summary>Removes a previously scheduled timeout</summary>
     /// <remarks>The token parameter is the value returned by <see cref="AddTimeout"/>.</remarks>
@@ -498,8 +497,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
     public static void Refresh ()
     {
         // TODO: Figure out how to remove this call to ClearContents. Refresh should just repaint damaged areas, not clear
-        Driver.ClearContents ();
-        View last = null;
+        Driver!.ClearContents ();
 
         foreach (Toplevel v in _topLevels.Reverse ())
         {
@@ -509,8 +507,6 @@ public static partial class Application // Run (Begin, Run, End, Stop)
                 v.SetSubViewNeedsDisplay ();
                 v.Draw ();
             }
-
-            last = v;
         }
 
         Driver.Refresh ();
@@ -518,11 +514,11 @@ public static partial class Application // Run (Begin, Run, End, Stop)
 
     /// <summary>This event is raised on each iteration of the main loop.</summary>
     /// <remarks>See also <see cref="Timeout"/></remarks>
-    public static event EventHandler<IterationEventArgs> Iteration;
+    public static event EventHandler<IterationEventArgs>? Iteration;
 
     /// <summary>The <see cref="MainLoop"/> driver for the application</summary>
     /// <value>The main loop.</value>
-    internal static MainLoop MainLoop { get; private set; }
+    internal static MainLoop? MainLoop { get; private set; }
 
     /// <summary>
     ///     Set to true to cause <see cref="End"/> to be called after the first iteration. Set to false (the default) to
@@ -661,17 +657,17 @@ public static partial class Application // Run (Begin, Run, End, Stop)
     ///         property on the currently running <see cref="Toplevel"/> to false.
     ///     </para>
     /// </remarks>
-    public static void RequestStop (Toplevel top = null)
+    public static void RequestStop (Toplevel? top = null)
     {
-        if (OverlappedTop is null || top is null || (OverlappedTop is null && top is { }))
+        if (OverlappedTop is null || top is null)
         {
             top = Current;
         }
 
         if (OverlappedTop != null
-            && top.IsOverlappedContainer
+            && top!.IsOverlappedContainer
             && top?.Running == true
-            && (Current?.Modal == false || (Current?.Modal == true && Current?.Running == false)))
+            && (Current?.Modal == false || Current is { Modal: true, Running: false }))
         {
             OverlappedTop.RequestStop ();
         }
@@ -679,7 +675,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
                  && top != Current
                  && Current?.Running == true
                  && Current?.Modal == true
-                 && top.Modal
+                 && top!.Modal
                  && top.Running)
         {
             var ev = new ToplevelClosingEventArgs (Current);
@@ -708,13 +704,13 @@ public static partial class Application // Run (Begin, Run, End, Stop)
                   && top != Current
                   && Current?.Modal == false
                   && Current?.Running == true
-                  && !top.Running)
+                  && !top!.Running)
                  || (OverlappedTop != null
                      && top != OverlappedTop
                      && top != Current
                      && Current?.Modal == false
                      && Current?.Running == false
-                     && !top.Running
+                     && !top!.Running
                      && _topLevels.ToArray () [1].Running))
         {
             MoveCurrent (top);
@@ -722,7 +718,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
         else if (OverlappedTop != null
                  && Current != top
                  && Current?.Running == true
-                 && !top.Running
+                 && !top!.Running
                  && Current?.Modal == true
                  && top.Modal)
         {
@@ -734,9 +730,9 @@ public static partial class Application // Run (Begin, Run, End, Stop)
                  && Current == top
                  && OverlappedTop?.Running == true
                  && Current?.Running == true
-                 && top.Running
+                 && top!.Running
                  && Current?.Modal == true
-                 && top.Modal)
+                 && top!.Modal)
         {
             // The OverlappedTop was requested to stop inside a modal Toplevel which is the Current and top,
             // both are the same, so needed to set the Current.Running to false too.
@@ -747,13 +743,13 @@ public static partial class Application // Run (Begin, Run, End, Stop)
         {
             Toplevel currentTop;
 
-            if (top == Current || (Current?.Modal == true && !top.Modal))
+            if (top == Current || (Current?.Modal == true && !top!.Modal))
             {
-                currentTop = Current;
+                currentTop = Current!;
             }
             else
             {
-                currentTop = top;
+                currentTop = top!;
             }
 
             if (!currentTop.Running)
diff --git a/Terminal.Gui/Application/Application.Toplevel.cs b/Terminal.Gui/Application/Application.Toplevel.cs
index d8996a383..e272ea7aa 100644
--- a/Terminal.Gui/Application/Application.Toplevel.cs
+++ b/Terminal.Gui/Application/Application.Toplevel.cs
@@ -10,7 +10,7 @@ public static partial class Application // Toplevel handling
 
     /// <summary>The <see cref="Toplevel"/> object used for the application on startup (<seealso cref="Top"/>)</summary>
     /// <value>The top.</value>
-    public static Toplevel Top { get; private set; }
+    public static Toplevel? Top { get; private set; }
 
     // TODO: Determine why this can't just return _topLevels.Peek()?
     /// <summary>
@@ -22,7 +22,7 @@ public static partial class Application // Toplevel handling
     ///     This will only be distinct from <see cref="Application.Top"/> in scenarios where <see cref="Toplevel.IsOverlappedContainer"/> is <see langword="true"/>.
     /// </remarks>
     /// <value>The current.</value>
-    public static Toplevel Current { get; private set; }
+    public static Toplevel? Current { get; private set; }
 
     /// <summary>
     ///     If <paramref name="topLevel"/> is not already Current and visible, finds the last Modal Toplevel in the stack and makes it Current.
@@ -195,7 +195,7 @@ public static partial class Application // Toplevel handling
     ///     Event handlers can set <see cref="SizeChangedEventArgs.Cancel"/> to <see langword="true"/> to prevent
     ///     <see cref="Application"/> from changing it's size to match the new terminal size.
     /// </remarks>
-    public static event EventHandler<SizeChangedEventArgs> SizeChanging;
+    public static event EventHandler<SizeChangedEventArgs>? SizeChanging;
 
     /// <summary>
     ///     Called when the application's size changes. Sets the size of all <see cref="Toplevel"/>s and fires the
diff --git a/Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs b/Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs
index cad728b72..8e6a08d59 100644
--- a/Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs
+++ b/Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs
@@ -1,3 +1,4 @@
+#nullable enable
 //
 // ConsoleDriver.cs: Base class for Terminal.Gui ConsoleDriver implementations.
 //
@@ -16,7 +17,7 @@ public abstract class ConsoleDriver
 {
     // As performance is a concern, we keep track of the dirty lines and only refresh those.
     // This is in addition to the dirty flag on each cell.
-    internal bool [] _dirtyLines;
+    internal bool []? _dirtyLines;
 
     // QUESTION: When non-full screen apps are supported, will this represent the app size, or will that be in Application?
     /// <summary>Gets the location and size of the terminal screen.</summary>
@@ -443,7 +444,7 @@ public abstract class ConsoleDriver
     public abstract bool SetCursorVisibility (CursorVisibility visibility);
 
     /// <summary>The event fired when the terminal is resized.</summary>
-    public event EventHandler<SizeChangedEventArgs> SizeChanged;
+    public event EventHandler<SizeChangedEventArgs>? SizeChanged;
 
     /// <summary>Suspends the application (e.g. on Linux via SIGTSTP) and upon resume, resets the console driver.</summary>
     /// <remarks>This is only implemented in <see cref="CursesDriver"/>.</remarks>
diff --git a/Terminal.Gui/View/Adornment/Margin.cs b/Terminal.Gui/View/Adornment/Margin.cs
index 046965e32..8ef63fe04 100644
--- a/Terminal.Gui/View/Adornment/Margin.cs
+++ b/Terminal.Gui/View/Adornment/Margin.cs
@@ -222,10 +222,10 @@ public class Margin : Adornment
         // Adjust the shadow such that it is drawn aligned with the Border
         if (ShadowStyle != ShadowStyle.None && _rightShadow is { } && _bottomShadow is { })
         {
-            _rightShadow.Y = Parent.Border.Thickness.Top > 0
+            _rightShadow.Y = Parent is { } && Parent.Border.Thickness.Top > 0
                                  ? Parent.Border.Thickness.Top - (Parent.Border.Thickness.Top > 2 && Parent.Border.Settings.FastHasFlags (BorderSettings.Title) ? 1 : 0)
                                  : 1;
-            _bottomShadow.X = Parent.Border.Thickness.Left > 0 ? Parent.Border.Thickness.Left : 1;
+            _bottomShadow.X = Parent is { } && Parent.Border.Thickness.Left > 0 ? Parent.Border.Thickness.Left : 1;
         }
     }
 }
diff --git a/Terminal.Gui/View/Adornment/ShadowView.cs b/Terminal.Gui/View/Adornment/ShadowView.cs
index c5e7a428a..ad06dc754 100644
--- a/Terminal.Gui/View/Adornment/ShadowView.cs
+++ b/Terminal.Gui/View/Adornment/ShadowView.cs
@@ -15,7 +15,7 @@ internal class ShadowView : View
         {
             var attr = Attribute.Default;
 
-            if (adornment.Parent.SuperView is { })
+            if (adornment.Parent?.SuperView is { })
             {
                 attr = adornment.Parent.SuperView.GetNormalColor ();
             }
diff --git a/Terminal.Gui/View/Layout/Dim.cs b/Terminal.Gui/View/Layout/Dim.cs
index 7dfc6eb2e..3102d5d3c 100644
--- a/Terminal.Gui/View/Layout/Dim.cs
+++ b/Terminal.Gui/View/Layout/Dim.cs
@@ -232,7 +232,7 @@ public abstract class Dim
         }
 
         var newDim = new DimCombine (AddOrSubtract.Add, left, right);
-        (left as DimView)?.Target.SetNeedsLayout ();
+        (left as DimView)?.Target?.SetNeedsLayout ();
 
         return newDim;
     }
diff --git a/Terminal.Gui/View/Layout/DimView.cs b/Terminal.Gui/View/Layout/DimView.cs
index 09ea96800..e95efd4fb 100644
--- a/Terminal.Gui/View/Layout/DimView.cs
+++ b/Terminal.Gui/View/Layout/DimView.cs
@@ -30,7 +30,7 @@ public class DimView : Dim
     public override bool Equals (object? other) { return other is DimView abs && abs.Target == Target && abs.Dimension == Dimension; }
 
     /// <inheritdoc/>
-    public override int GetHashCode () { return Target.GetHashCode (); }
+    public override int GetHashCode () { return Target!.GetHashCode (); }
 
     /// <summary>
     ///     Gets the View the dimension is anchored to.
diff --git a/Terminal.Gui/View/Layout/Pos.cs b/Terminal.Gui/View/Layout/Pos.cs
index 853bfa0ab..63e14b67f 100644
--- a/Terminal.Gui/View/Layout/Pos.cs
+++ b/Terminal.Gui/View/Layout/Pos.cs
@@ -379,7 +379,7 @@ public abstract class Pos
 
         if (left is PosView view)
         {
-            view.Target.SetNeedsLayout ();
+            view.Target?.SetNeedsLayout ();
         }
 
         return newPos;
@@ -408,7 +408,7 @@ public abstract class Pos
 
         if (left is PosView view)
         {
-            view.Target.SetNeedsLayout ();
+            view.Target?.SetNeedsLayout ();
         }
 
         return newPos;
diff --git a/Terminal.Gui/View/Layout/PosView.cs b/Terminal.Gui/View/Layout/PosView.cs
index fdf5bf784..8ceba980f 100644
--- a/Terminal.Gui/View/Layout/PosView.cs
+++ b/Terminal.Gui/View/Layout/PosView.cs
@@ -28,7 +28,7 @@ public class PosView (View? view, Side side) : Pos
     public override bool Equals (object? other) { return other is PosView abs && abs.Target == Target && abs.Side == Side; }
 
     /// <inheritdoc/>
-    public override int GetHashCode () { return Target.GetHashCode (); }
+    public override int GetHashCode () { return Target!.GetHashCode (); }
 
     /// <inheritdoc/>
     public override string ToString ()
diff --git a/Terminal.Gui/Views/Menu/MenuBar.cs b/Terminal.Gui/Views/Menu/MenuBar.cs
index 0b4e574de..3428b2c93 100644
--- a/Terminal.Gui/Views/Menu/MenuBar.cs
+++ b/Terminal.Gui/Views/Menu/MenuBar.cs
@@ -1594,7 +1594,7 @@ public class MenuBar : View, IDesignable
 
 
     /// <inheritdoc />
-    public bool EnableForDesign<TContext> (in TContext context) where TContext : notnull
+    public bool EnableForDesign<TContext> (ref readonly TContext context) where TContext : notnull
     {
         if (context is not Func<string, bool> actionFn)
         {
diff --git a/UICatalog/UICatalog.cs b/UICatalog/UICatalog.cs
index dd18f0bd1..a2cc9a474 100644
--- a/UICatalog/UICatalog.cs
+++ b/UICatalog/UICatalog.cs
@@ -715,7 +715,7 @@ internal class UICatalogApp
                                    }
 
                                    ColorScheme = Colors.ColorSchemes [_topLevelColorScheme];
-                                   Application.Top.SetNeedsDisplay ();
+                                   Application.Top!.SetNeedsDisplay ();
                                };
                 schemeMenuItems.Add (item);
             }
diff --git a/UnitTests/Views/MenuBarTests.cs b/UnitTests/Views/MenuBarTests.cs
index 35d08beff..6f9de4683 100644
--- a/UnitTests/Views/MenuBarTests.cs
+++ b/UnitTests/Views/MenuBarTests.cs
@@ -1,6 +1,4 @@
-using UICatalog.Scenarios;
-using Xunit.Abstractions;
-
+using Xunit.Abstractions;
 
 namespace Terminal.Gui.ViewsTests;
 
@@ -34,13 +32,13 @@ public class MenuBarTests (ITestOutputHelper output)
 
         Assert.True (
                      menu.NewMouseEvent (
-                                         new() { Position = new (0, 0), Flags = MouseFlags.Button1Pressed, View = menu }
+                                         new () { Position = new (0, 0), Flags = MouseFlags.Button1Pressed, View = menu }
                                         )
                     );
 
         Assert.True (
                      menu._openMenu.NewMouseEvent (
-                                                   new() { Position = new (0, 0), Flags = MouseFlags.Button1Clicked, View = menu._openMenu }
+                                                   new () { Position = new (0, 0), Flags = MouseFlags.Button1Clicked, View = menu._openMenu }
                                                   )
                     );
         Application.MainLoop.RunIteration ();
@@ -54,7 +52,7 @@ public class MenuBarTests (ITestOutputHelper output)
 
         Assert.True (
                      menu.NewMouseEvent (
-                                         new() { Position = new (0, 0), Flags = MouseFlags.Button1Pressed, View = menu }
+                                         new () { Position = new (0, 0), Flags = MouseFlags.Button1Pressed, View = menu }
                                         )
                     );
         Application.Refresh ();
@@ -63,16 +61,14 @@ public class MenuBarTests (ITestOutputHelper output)
                                                       @$"
  Nullable Checked       
 ┌──────────────────────┐
-│ {
-    CM.Glyphs.CheckStateNone
-} Check this out 你  │
+│ {CM.Glyphs.CheckStateNone} Check this out 你  │
 └──────────────────────┘",
                                                       output
                                                      );
 
         Assert.True (
                      menu._openMenu.NewMouseEvent (
-                                                   new() { Position = new (0, 0), Flags = MouseFlags.Button1Clicked, View = menu._openMenu }
+                                                   new () { Position = new (0, 0), Flags = MouseFlags.Button1Clicked, View = menu._openMenu }
                                                   )
                     );
         Application.MainLoop.RunIteration ();
@@ -84,13 +80,13 @@ public class MenuBarTests (ITestOutputHelper output)
 
         Assert.True (
                      menu.NewMouseEvent (
-                                         new() { Position = new (0, 0), Flags = MouseFlags.Button1Pressed, View = menu }
+                                         new () { Position = new (0, 0), Flags = MouseFlags.Button1Pressed, View = menu }
                                         )
                     );
 
         Assert.True (
                      menu._openMenu.NewMouseEvent (
-                                                   new() { Position = new (0, 0), Flags = MouseFlags.Button1Clicked, View = menu._openMenu }
+                                                   new () { Position = new (0, 0), Flags = MouseFlags.Button1Clicked, View = menu._openMenu }
                                                   )
                     );
         Application.MainLoop.RunIteration ();
@@ -185,7 +181,7 @@ public class MenuBarTests (ITestOutputHelper output)
         Assert.True (menuBar.WantMousePositionReports);
         Assert.False (menuBar.IsMenuOpen);
 
-        menuBar = new() { Menus = [] };
+        menuBar = new () { Menus = [] };
         Assert.Equal (0, menuBar.X);
         Assert.Equal (0, menuBar.Y);
         Assert.IsType<DimFill> (menuBar.Width);
@@ -296,7 +292,7 @@ public class MenuBarTests (ITestOutputHelper output)
 
         Assert.True (
                      menu.NewMouseEvent (
-                                         new() { Position = new (0, 0), Flags = MouseFlags.Button1Pressed, View = menu }
+                                         new () { Position = new (0, 0), Flags = MouseFlags.Button1Pressed, View = menu }
                                         )
                     );
         top.Draw ();
@@ -317,7 +313,7 @@ public class MenuBarTests (ITestOutputHelper output)
         Assert.True (
                      top.Subviews [1]
                         .NewMouseEvent (
-                                        new() { Position = new (0, 2), Flags = MouseFlags.Button1Clicked, View = top.Subviews [1] }
+                                        new () { Position = new (0, 2), Flags = MouseFlags.Button1Clicked, View = top.Subviews [1] }
                                        )
                     );
         top.Subviews [1].Draw ();
@@ -338,7 +334,7 @@ public class MenuBarTests (ITestOutputHelper output)
         Assert.True (
                      top.Subviews [1]
                         .NewMouseEvent (
-                                        new() { Position = new (0, 2), Flags = MouseFlags.ReportMousePosition, View = top.Subviews [1] }
+                                        new () { Position = new (0, 2), Flags = MouseFlags.ReportMousePosition, View = top.Subviews [1] }
                                        )
                     );
         top.Subviews [1].Draw ();
@@ -516,7 +512,7 @@ public class MenuBarTests (ITestOutputHelper output)
                                                       output
                                                      );
 
-        Application.OnMouseEvent (new() { Position = new (20, 5), Flags = MouseFlags.Button1Clicked });
+        Application.OnMouseEvent (new () { Position = new (20, 5), Flags = MouseFlags.Button1Clicked });
 
         firstIteration = false;
 
@@ -549,7 +545,7 @@ public class MenuBarTests (ITestOutputHelper output)
         {
             menu.OpenMenu ();
 
-            Application.OnMouseEvent (new() { Position = new (20, 5 + i), Flags = MouseFlags.Button1Clicked });
+            Application.OnMouseEvent (new () { Position = new (20, 5 + i), Flags = MouseFlags.Button1Clicked });
 
             firstIteration = false;
             Application.RunIteration (ref rsDialog, ref firstIteration);
@@ -705,7 +701,7 @@ public class MenuBarTests (ITestOutputHelper output)
                                                       output
                                                      );
 
-        Application.OnMouseEvent (new() { Position = new (20, 5), Flags = MouseFlags.Button1Clicked });
+        Application.OnMouseEvent (new () { Position = new (20, 5), Flags = MouseFlags.Button1Clicked });
 
         firstIteration = false;
 
@@ -727,7 +723,7 @@ public class MenuBarTests (ITestOutputHelper output)
         {
             menu.OpenMenu ();
 
-            Application.OnMouseEvent (new() { Position = new (20, 5 + i), Flags = MouseFlags.Button1Clicked });
+            Application.OnMouseEvent (new () { Position = new (20, 5 + i), Flags = MouseFlags.Button1Clicked });
 
             firstIteration = false;
             Application.RunIteration (ref rs, ref firstIteration);
@@ -1253,15 +1249,15 @@ wo
         MenuItem mbiCurrent = null;
         MenuItem miCurrent = null;
 
-        MenuBar menu = new MenuBar ();
-        menu.EnableForDesign (
-                               new Func<object, bool> (s =>
-                                                       {
-                                                           miAction = s as string;
+        var menu = new MenuBar ();
 
-                                                           return true;
-                                                       })
-                              );
+        Func<object, bool> fn = s =>
+                                {
+                                    miAction = s as string;
+
+                                    return true;
+                                };
+        menu.EnableForDesign (ref fn);
 
         menu.Key = KeyCode.F9;
         menu.MenuOpening += (s, e) => mbiCurrent = e.CurrentMenu;
@@ -1303,15 +1299,17 @@ wo
         MenuItem mbiCurrent = null;
         MenuItem miCurrent = null;
 
-        MenuBar menu = new MenuBar ();
-        menu.EnableForDesign (
-                               new Func<object, bool> (s =>
-                                                       {
-                                                           miAction = s as string;
+        var menu = new MenuBar ();
 
-                                                           return true;
-                                                       })
-                              );
+        menu.EnableForDesign (
+                              new Func<object, bool> (
+                                                      s =>
+                                                      {
+                                                          miAction = s as string;
+
+                                                          return true;
+                                                      })
+                             );
 
         menu.Key = KeyCode.F9;
         menu.MenuOpening += (s, e) => mbiCurrent = e.CurrentMenu;
@@ -1478,13 +1476,13 @@ wo
         top.Add (menu);
         Application.Begin (top);
 
-        Assert.True (menu.NewMouseEvent (new() { Position = new (1, 0), Flags = MouseFlags.Button1Pressed, View = menu }));
+        Assert.True (menu.NewMouseEvent (new () { Position = new (1, 0), Flags = MouseFlags.Button1Pressed, View = menu }));
         Assert.True (menu.IsMenuOpen);
         top.Draw ();
 
         TestHelpers.AssertDriverContentsAre (expectedMenu.ExpectedSubMenuOpen (0), output);
 
-        Assert.True (menu.NewMouseEvent (new() { Position = new (1, 0), Flags = MouseFlags.Button1Pressed, View = menu }));
+        Assert.True (menu.NewMouseEvent (new () { Position = new (1, 0), Flags = MouseFlags.Button1Pressed, View = menu }));
         Assert.False (menu.IsMenuOpen);
         top.Draw ();
         TestHelpers.AssertDriverContentsAre (expectedMenu.ClosedMenuText, output);
@@ -1985,7 +1983,7 @@ wo
         top.Remove (menu);
 
         // Now test WITH HotKeys
-        menu = new()
+        menu = new ()
         {
             Menus =
             [
@@ -2114,9 +2112,9 @@ wo
         {
             Menus =
             [
-                new() { Title = "Test 1", Action = () => { } },
+                new () { Title = "Test 1", Action = () => { } },
 
-                new() { Title = "Test 2", Action = () => { } }
+                new () { Title = "Test 2", Action = () => { } }
             ]
         };
 
@@ -2204,7 +2202,7 @@ wo
         // open the menu
         Assert.True (
                      menu.NewMouseEvent (
-                                         new() { Position = new (1, 0), Flags = MouseFlags.Button1Pressed, View = menu }
+                                         new () { Position = new (1, 0), Flags = MouseFlags.Button1Pressed, View = menu }
                                         )
                     );
         Assert.True (menu.IsMenuOpen);
@@ -2213,7 +2211,7 @@ wo
 
         Assert.True (
                      mCurrent.NewMouseEvent (
-                                             new() { Position = new (1, 1), Flags = MouseFlags.ReportMousePosition, View = mCurrent }
+                                             new () { Position = new (1, 1), Flags = MouseFlags.ReportMousePosition, View = mCurrent }
                                             )
                     );
         Assert.True (menu.IsMenuOpen);
@@ -2222,7 +2220,7 @@ wo
 
         Assert.True (
                      mCurrent.NewMouseEvent (
-                                             new() { Position = new (1, 1), Flags = MouseFlags.ReportMousePosition, View = mCurrent }
+                                             new () { Position = new (1, 1), Flags = MouseFlags.ReportMousePosition, View = mCurrent }
                                             )
                     );
         Assert.True (menu.IsMenuOpen);
@@ -2231,7 +2229,7 @@ wo
 
         Assert.True (
                      mCurrent.NewMouseEvent (
-                                             new() { Position = new (1, 2), Flags = MouseFlags.ReportMousePosition, View = mCurrent }
+                                             new () { Position = new (1, 2), Flags = MouseFlags.ReportMousePosition, View = mCurrent }
                                             )
                     );
         Assert.True (menu.IsMenuOpen);
@@ -2241,7 +2239,7 @@ wo
         // close the menu
         Assert.True (
                      menu.NewMouseEvent (
-                                         new() { Position = new (1, 0), Flags = MouseFlags.Button1Pressed, View = menu }
+                                         new () { Position = new (1, 0), Flags = MouseFlags.Button1Pressed, View = menu }
                                         )
                     );
         Assert.False (menu.IsMenuOpen);
@@ -2411,7 +2409,7 @@ Edit
         // Click on Edit
         Assert.True (
                      menu.NewMouseEvent (
-                                         new() { Position = new (10, 0), Flags = MouseFlags.Button1Pressed, View = menu }
+                                         new () { Position = new (10, 0), Flags = MouseFlags.Button1Pressed, View = menu }
                                         )
                     );
         Assert.True (menu.IsMenuOpen);
@@ -2421,7 +2419,7 @@ Edit
         // Click on Paste
         Assert.True (
                      mCurrent.NewMouseEvent (
-                                             new() { Position = new (10, 2), Flags = MouseFlags.ReportMousePosition, View = mCurrent }
+                                             new () { Position = new (10, 2), Flags = MouseFlags.ReportMousePosition, View = mCurrent }
                                             )
                     );
         Assert.True (menu.IsMenuOpen);
@@ -2435,7 +2433,7 @@ Edit
                 // Edit menu is open. Click on the menu at Y = -1, which is outside the menu.
                 Assert.False (
                               mCurrent.NewMouseEvent (
-                                                      new() { Position = new (10, i), Flags = MouseFlags.ReportMousePosition, View = menu }
+                                                      new () { Position = new (10, i), Flags = MouseFlags.ReportMousePosition, View = menu }
                                                      )
                              );
             }
@@ -2444,7 +2442,7 @@ Edit
                 // Edit menu is open. Click on the menu at Y = i.
                 Assert.True (
                              mCurrent.NewMouseEvent (
-                                                     new() { Position = new (10, i), Flags = MouseFlags.ReportMousePosition, View = mCurrent }
+                                                     new () { Position = new (10, i), Flags = MouseFlags.ReportMousePosition, View = mCurrent }
                                                     )
                             );
             }
@@ -2609,7 +2607,7 @@ Edit
         Application.Begin (top);
 
         Assert.True (tf.HasFocus);
-        Assert.True (menu.NewMouseEvent (new() { Position = new (1, 0), Flags = MouseFlags.Button1Pressed, View = menu }));
+        Assert.True (menu.NewMouseEvent (new () { Position = new (1, 0), Flags = MouseFlags.Button1Pressed, View = menu }));
         Assert.True (menu.IsMenuOpen);
         Assert.False (tf.HasFocus);
         top.Draw ();
@@ -2617,7 +2615,7 @@ Edit
 
         Assert.True (
                      menu.NewMouseEvent (
-                                         new() { Position = new (8, 0), Flags = MouseFlags.ReportMousePosition, View = menu }
+                                         new () { Position = new (8, 0), Flags = MouseFlags.ReportMousePosition, View = menu }
                                         )
                     );
         Assert.True (menu.IsMenuOpen);
@@ -2627,7 +2625,7 @@ Edit
 
         Assert.True (
                      menu.NewMouseEvent (
-                                         new() { Position = new (15, 0), Flags = MouseFlags.ReportMousePosition, View = menu }
+                                         new () { Position = new (15, 0), Flags = MouseFlags.ReportMousePosition, View = menu }
                                         )
                     );
         Assert.True (menu.IsMenuOpen);
@@ -2637,7 +2635,7 @@ Edit
 
         Assert.True (
                      menu.NewMouseEvent (
-                                         new() { Position = new (8, 0), Flags = MouseFlags.ReportMousePosition, View = menu }
+                                         new () { Position = new (8, 0), Flags = MouseFlags.ReportMousePosition, View = menu }
                                         )
                     );
         Assert.True (menu.IsMenuOpen);
@@ -2647,7 +2645,7 @@ Edit
 
         Assert.True (
                      menu.NewMouseEvent (
-                                         new() { Position = new (1, 0), Flags = MouseFlags.ReportMousePosition, View = menu }
+                                         new () { Position = new (1, 0), Flags = MouseFlags.ReportMousePosition, View = menu }
                                         )
                     );
         Assert.True (menu.IsMenuOpen);
@@ -2655,7 +2653,7 @@ Edit
         top.Draw ();
         TestHelpers.AssertDriverContentsAre (expectedMenu.ExpectedSubMenuOpen (0), output);
 
-        Assert.True (menu.NewMouseEvent (new() { Position = new (8, 0), Flags = MouseFlags.Button1Pressed, View = menu }));
+        Assert.True (menu.NewMouseEvent (new () { Position = new (8, 0), Flags = MouseFlags.Button1Pressed, View = menu }));
         Assert.False (menu.IsMenuOpen);
         Assert.True (tf.HasFocus);
         top.Draw ();
@@ -2991,7 +2989,7 @@ Edit
 
         Assert.True (
                      menu.NewMouseEvent (
-                                         new() { Position = new (1, 0), Flags = MouseFlags.Button1Pressed, View = menu }
+                                         new () { Position = new (1, 0), Flags = MouseFlags.Button1Pressed, View = menu }
                                         )
                     );
         top.Draw ();
@@ -3010,7 +3008,7 @@ Edit
 
         Assert.False (
                       menu.NewMouseEvent (
-                                          new()
+                                          new ()
                                           {
                                               Position = new (1, 2), Flags = MouseFlags.ReportMousePosition, View = Application.Top.Subviews [1]
                                           }
@@ -3033,7 +3031,7 @@ Edit
 
         Assert.False (
                       menu.NewMouseEvent (
-                                          new()
+                                          new ()
                                           {
                                               Position = new (1, 1), Flags = MouseFlags.ReportMousePosition, View = Application.Top.Subviews [1]
                                           }
@@ -3055,7 +3053,7 @@ Edit
 
         Assert.False (
                       menu.NewMouseEvent (
-                                          new() { Position = new (70, 2), Flags = MouseFlags.Button1Clicked, View = Application.Top }
+                                          new () { Position = new (70, 2), Flags = MouseFlags.Button1Clicked, View = Application.Top }
                                          )
                      );
         top.Draw ();
@@ -3488,7 +3486,7 @@ Edit
 
         Assert.True (
                      menu.NewMouseEvent (
-                                         new() { Position = new (1, 0), Flags = MouseFlags.Button1Pressed, View = menu }
+                                         new () { Position = new (1, 0), Flags = MouseFlags.Button1Pressed, View = menu }
                                         )
                     );
         top.Draw ();
@@ -3505,7 +3503,7 @@ Edit
 
         Assert.False (
                       menu.NewMouseEvent (
-                                          new() { Position = new (1, 2), Flags = MouseFlags.Button1Clicked, View = Application.Top.Subviews [1] }
+                                          new () { Position = new (1, 2), Flags = MouseFlags.Button1Clicked, View = Application.Top.Subviews [1] }
                                          )
                      );
         top.Draw ();
@@ -3523,7 +3521,7 @@ Edit
 
         Assert.False (
                       menu.NewMouseEvent (
-                                          new() { Position = new (1, 1), Flags = MouseFlags.Button1Clicked, View = Application.Top.Subviews [2] }
+                                          new () { Position = new (1, 1), Flags = MouseFlags.Button1Clicked, View = Application.Top.Subviews [2] }
                                          )
                      );
         top.Draw ();
@@ -3540,7 +3538,7 @@ Edit
 
         Assert.False (
                       menu.NewMouseEvent (
-                                          new() { Position = new (70, 2), Flags = MouseFlags.Button1Clicked, View = Application.Top }
+                                          new () { Position = new (70, 2), Flags = MouseFlags.Button1Clicked, View = Application.Top }
                                          )
                      );
         top.Draw ();
@@ -3619,13 +3617,7 @@ Edit
 
         public string ExpectedBottomRow (int i)
         {
-            return $"{
-                CM.Glyphs.LLCorner
-            }{
-                new (CM.Glyphs.HLine.ToString () [0], Menus [i].Children [0].TitleLength + 3)
-            }{
-                CM.Glyphs.LRCorner
-            }  \n";
+            return $"{CM.Glyphs.LLCorner}{new (CM.Glyphs.HLine.ToString () [0], Menus [i].Children [0].TitleLength + 3)}{CM.Glyphs.LRCorner}  \n";
         }
 
         // The 3 spaces at end are a result of Menu.cs line 1062 where `pos` is calculated (` + spacesAfterTitle`)
@@ -3654,13 +3646,7 @@ Edit
         //   1 space before the Title and 2 spaces after the Title/Check/Help
         public string ExpectedTopRow (int i)
         {
-            return $"{
-                CM.Glyphs.ULCorner
-            }{
-                new (CM.Glyphs.HLine.ToString () [0], Menus [i].Children [0].TitleLength + 3)
-            }{
-                CM.Glyphs.URCorner
-            }  \n";
+            return $"{CM.Glyphs.ULCorner}{new (CM.Glyphs.HLine.ToString () [0], Menus [i].Children [0].TitleLength + 3)}{CM.Glyphs.URCorner}  \n";
         }
 
         // Padding for the X of the sub menu Frame
diff --git a/UnitTests/Views/ToplevelTests.cs b/UnitTests/Views/ToplevelTests.cs
index 2d4a0a323..624da69ac 100644
--- a/UnitTests/Views/ToplevelTests.cs
+++ b/UnitTests/Views/ToplevelTests.cs
@@ -491,7 +491,7 @@ public partial class ToplevelTests (ITestOutputHelper output)
         Assert.Equal (tf1W2, top.MostFocused);
         Assert.True (Application.OnKeyDown (Key.CursorRight)); // move char to right in tf1W2
         Assert.Equal (win2, top.Focused);
-        Assert.Equal (tf1W2, top.MostFocused);   
+        Assert.Equal (tf1W2, top.MostFocused);
         Assert.True (Application.OnKeyDown (Key.CursorDown)); // move down to next view (tvW2)
         Assert.Equal (win2, top.Focused);
         Assert.Equal (tvW2, top.MostFocused);
@@ -504,7 +504,7 @@ public partial class ToplevelTests (ITestOutputHelper output)
         Assert.Equal (win2, top.Focused);
         Assert.Equal (tvW2, top.MostFocused);
         tvW2.AllowsTab = false;
-        Assert.True (Application.OnKeyDown (Key.Tab.WithShift)); 
+        Assert.True (Application.OnKeyDown (Key.Tab.WithShift));
         Assert.Equal (win2, top.Focused);
         Assert.Equal (tf1W2, top.MostFocused);
         Assert.True (Application.OnKeyDown (Key.CursorLeft));
@@ -563,9 +563,6 @@ public partial class ToplevelTests (ITestOutputHelper output)
     [Fact]
     public void Added_Event_Should_Not_Be_Used_To_Initialize_Toplevel_Events ()
     {
-        Key alternateForwardKey = default;
-        Key alternateBackwardKey = default;
-        Key quitKey = default;
         var wasAdded = false;
 
         var view = new View ();
@@ -588,7 +585,7 @@ public partial class ToplevelTests (ITestOutputHelper output)
 
         Application.Shutdown ();
     }
-    
+
     [Fact]
     [AutoInitShutdown]
     public void Mouse_Drag_On_Top_With_Superview_Null ()

From 04dbe68dbf72725dbcbdbcc0700fa142b7606503 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Wed, 24 Jul 2024 14:20:08 -0600
Subject: [PATCH 19/33] Fixed nullable warnings 3

---
 Terminal.Gui/Application/Application.Run.cs | 37 ++++++++++-----------
 1 file changed, 17 insertions(+), 20 deletions(-)

diff --git a/Terminal.Gui/Application/Application.Run.cs b/Terminal.Gui/Application/Application.Run.cs
index bbff9c1ba..9a79af3d4 100644
--- a/Terminal.Gui/Application/Application.Run.cs
+++ b/Terminal.Gui/Application/Application.Run.cs
@@ -537,7 +537,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
 
         for (state.Toplevel.Running = true; state.Toplevel?.Running == true;)
         {
-            MainLoop.Running = true;
+            MainLoop!.Running = true;
 
             if (EndAfterFirstIteration && !firstIteration)
             {
@@ -547,7 +547,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             RunIteration (ref state, ref firstIteration);
         }
 
-        MainLoop.Running = false;
+        MainLoop!.Running = false;
 
         // Run one last iteration to consume any outstanding input events from Driver
         // This is important for remaining OnKeyUp events.
@@ -562,7 +562,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
     /// </param>
     public static void RunIteration (ref RunState state, ref bool firstIteration)
     {
-        if (MainLoop.Running && MainLoop.EventsPending ())
+        if (MainLoop!.Running && MainLoop.EventsPending ())
         {
             // Notify Toplevel it's ready
             if (firstIteration)
@@ -580,7 +580,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
                 OverlappedTop?.OnDeactivate (state.Toplevel);
                 state.Toplevel = Current;
                 OverlappedTop?.OnActivate (state.Toplevel);
-                Top.SetSubViewNeedsDisplay ();
+                Top!.SetSubViewNeedsDisplay ();
                 Refresh ();
             }
         }
@@ -592,9 +592,9 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             return;
         }
 
-        if (state.Toplevel != Top && (Top.NeedsDisplay || Top.SubViewNeedsDisplay || Top.LayoutNeeded))
+        if (state.Toplevel != Top && (Top!.NeedsDisplay || Top.SubViewNeedsDisplay || Top.LayoutNeeded))
         {
-            state.Toplevel.SetNeedsDisplay (state.Toplevel.Frame);
+            state.Toplevel!.SetNeedsDisplay (state.Toplevel.Frame);
             Top.Draw ();
 
             foreach (Toplevel top in _topLevels.Reverse ())
@@ -610,8 +610,8 @@ public static partial class Application // Run (Begin, Run, End, Stop)
 
         if (_topLevels.Count == 1
             && state.Toplevel == Top
-            && (Driver.Cols != state.Toplevel.Frame.Width
-                || Driver.Rows != state.Toplevel.Frame.Height)
+            && (Driver!.Cols != state.Toplevel!.Frame.Width
+                || Driver!.Rows != state.Toplevel.Frame.Height)
             && (state.Toplevel.NeedsDisplay
                 || state.Toplevel.SubViewNeedsDisplay
                 || state.Toplevel.LayoutNeeded))
@@ -619,18 +619,18 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             Driver.ClearContents ();
         }
 
-        if (state.Toplevel.NeedsDisplay || state.Toplevel.SubViewNeedsDisplay || state.Toplevel.LayoutNeeded || OverlappedChildNeedsDisplay ())
+        if (state.Toplevel!.NeedsDisplay || state.Toplevel.SubViewNeedsDisplay || state.Toplevel.LayoutNeeded || OverlappedChildNeedsDisplay ())
         {
             state.Toplevel.SetNeedsDisplay ();
             state.Toplevel.Draw ();
-            Driver.UpdateScreen ();
+            Driver!.UpdateScreen ();
 
             //Driver.UpdateCursor ();
         }
 
         if (PositionCursor (state.Toplevel))
         {
-            Driver.UpdateCursor ();
+            Driver!.UpdateCursor ();
         }
 
         //        else
@@ -642,7 +642,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             //Driver.UpdateCursor ();
         }
 
-        if (state.Toplevel != Top && !state.Toplevel.Modal && (Top.NeedsDisplay || Top.SubViewNeedsDisplay || Top.LayoutNeeded))
+        if (state.Toplevel != Top && !state.Toplevel.Modal && (Top!.NeedsDisplay || Top.SubViewNeedsDisplay || Top.LayoutNeeded))
         {
             Top.Draw ();
         }
@@ -673,8 +673,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
         }
         else if (OverlappedTop != null
                  && top != Current
-                 && Current?.Running == true
-                 && Current?.Modal == true
+                 && Current is { Running: true, Modal: true }
                  && top!.Modal
                  && top.Running)
         {
@@ -702,14 +701,12 @@ public static partial class Application // Run (Begin, Run, End, Stop)
         else if ((OverlappedTop != null
                   && top != OverlappedTop
                   && top != Current
-                  && Current?.Modal == false
-                  && Current?.Running == true
+                  && Current is { Modal: false, Running: true }
                   && !top!.Running)
                  || (OverlappedTop != null
                      && top != OverlappedTop
                      && top != Current
-                     && Current?.Modal == false
-                     && Current?.Running == false
+                     && Current is { Modal: false, Running: false }
                      && !top!.Running
                      && _topLevels.ToArray () [1].Running))
         {
@@ -815,7 +812,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
 
         // If there is a OverlappedTop that is not the RunState.Toplevel then RunState.Toplevel
         // is a child of MidTop, and we should notify the OverlappedTop that it is closing
-        if (OverlappedTop is { } && !runState.Toplevel.Modal && runState.Toplevel != OverlappedTop)
+        if (OverlappedTop is { } && !runState.Toplevel!.Modal && runState.Toplevel != OverlappedTop)
         {
             OverlappedTop.OnChildClosed (runState.Toplevel);
         }
@@ -841,7 +838,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             else
             {
                 SetCurrentOverlappedAsTop ();
-                runState.Toplevel.OnLeave (Current);
+                runState.Toplevel!.OnLeave (Current);
                 Current.OnEnter (runState.Toplevel);
             }
 

From 3b351891067d6677fa501df33993842d3a098b7d Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Wed, 24 Jul 2024 14:36:20 -0600
Subject: [PATCH 20/33] Fixed nullable warnings 4

---
 .../Application/Application.Toplevel.cs       |  15 +-
 Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs  | 201 +++++++++---------
 2 files changed, 116 insertions(+), 100 deletions(-)

diff --git a/Terminal.Gui/Application/Application.Toplevel.cs b/Terminal.Gui/Application/Application.Toplevel.cs
index e272ea7aa..d45360d64 100644
--- a/Terminal.Gui/Application/Application.Toplevel.cs
+++ b/Terminal.Gui/Application/Application.Toplevel.cs
@@ -59,7 +59,7 @@ public static partial class Application // Toplevel handling
     /// <param name="start"></param>
     /// <param name="location"></param>
     /// <returns></returns>
-    private static Toplevel FindDeepestTop (Toplevel start, in Point location)
+    private static Toplevel? FindDeepestTop (Toplevel start, in Point location)
     {
         if (!start.Frame.Contains (location))
         {
@@ -91,15 +91,20 @@ public static partial class Application // Toplevel handling
     /// <summary>
     /// Given <paramref name="view"/>, returns the first Superview up the chain that is <see cref="Top"/>.
     /// </summary>
-    private static View FindTopFromView (View view)
+    private static View? FindTopFromView (View? view)
     {
-        View top = view?.SuperView is { } && view?.SuperView != Top
+        if (view is null)
+        {
+            return null;
+        }
+
+        View top = view.SuperView is { } && view.SuperView != Top
                        ? view.SuperView
                        : view;
 
         while (top?.SuperView is { } && top?.SuperView != Top)
         {
-            top = top.SuperView;
+            top = top!.SuperView;
         }
 
         return top;
@@ -221,7 +226,7 @@ public static partial class Application // Toplevel handling
 
             if (PositionCursor (t))
             {
-                Driver.UpdateCursor ();
+                Driver?.UpdateCursor ();
             }
         }
 
diff --git a/Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs b/Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs
index 8e6a08d59..5e9a7dad3 100644
--- a/Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs
+++ b/Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs
@@ -46,7 +46,7 @@ public abstract class ConsoleDriver
     }
 
     /// <summary>Get the operating system clipboard.</summary>
-    public IClipboard Clipboard { get; internal set; }
+    public IClipboard? Clipboard { get; internal set; }
 
     /// <summary>
     ///     Gets the column last set by <see cref="Move"/>. <see cref="Col"/> and <see cref="Row"/> are used by
@@ -70,7 +70,7 @@ public abstract class ConsoleDriver
     ///     <see cref="UpdateScreen"/> is called.
     ///     <remarks>The format of the array is rows, columns. The first index is the row, the second index is the column.</remarks>
     /// </summary>
-    public Cell [,] Contents { get; internal set; }
+    public Cell [,]? Contents { get; internal set; }
 
     /// <summary>The leftmost column in the terminal.</summary>
     public virtual int Left { get; internal set; } = 0;
@@ -125,125 +125,133 @@ public abstract class ConsoleDriver
         int runeWidth = -1;
         bool validLocation = IsValidLocation (Col, Row);
 
+        if (Contents is null)
+        {
+            return;
+        }
+
         if (validLocation)
         {
             rune = rune.MakePrintable ();
             runeWidth = rune.GetColumns ();
 
-            if (runeWidth == 0 && rune.IsCombiningMark ())
+            lock (Contents)
             {
-                // AtlasEngine does not support NON-NORMALIZED combining marks in a way
-                // compatible with the driver architecture. Any CMs (except in the first col)
-                // are correctly combined with the base char, but are ALSO treated as 1 column
-                // width codepoints E.g. `echo "[e`u{0301}`u{0301}]"` will output `[é  ]`.
-                // 
-                // Until this is addressed (see Issue #), we do our best by 
-                // a) Attempting to normalize any CM with the base char to it's left
-                // b) Ignoring any CMs that don't normalize
-                if (Col > 0)
+                if (runeWidth == 0 && rune.IsCombiningMark ())
                 {
-                    if (Contents [Row, Col - 1].CombiningMarks.Count > 0)
+                    // AtlasEngine does not support NON-NORMALIZED combining marks in a way
+                    // compatible with the driver architecture. Any CMs (except in the first col)
+                    // are correctly combined with the base char, but are ALSO treated as 1 column
+                    // width codepoints E.g. `echo "[e`u{0301}`u{0301}]"` will output `[é  ]`.
+                    // 
+                    // Until this is addressed (see Issue #), we do our best by 
+                    // a) Attempting to normalize any CM with the base char to it's left
+                    // b) Ignoring any CMs that don't normalize
+                    if (Col > 0)
                     {
-                        // Just add this mark to the list
-                        Contents [Row, Col - 1].CombiningMarks.Add (rune);
-
-                        // Ignore. Don't move to next column (let the driver figure out what to do).
-                    }
-                    else
-                    {
-                        // Attempt to normalize the cell to our left combined with this mark
-                        string combined = Contents [Row, Col - 1].Rune + rune.ToString ();
-
-                        // Normalize to Form C (Canonical Composition)
-                        string normalized = combined.Normalize (NormalizationForm.FormC);
-
-                        if (normalized.Length == 1)
+                        if (Contents [Row, Col - 1].CombiningMarks.Count > 0)
                         {
-                            // It normalized! We can just set the Cell to the left with the
-                            // normalized codepoint 
-                            Contents [Row, Col - 1].Rune = (Rune)normalized [0];
-
-                            // Ignore. Don't move to next column because we're already there
-                        }
-                        else
-                        {
-                            // It didn't normalize. Add it to the Cell to left's CM list
+                            // Just add this mark to the list
                             Contents [Row, Col - 1].CombiningMarks.Add (rune);
 
                             // Ignore. Don't move to next column (let the driver figure out what to do).
                         }
-                    }
+                        else
+                        {
+                            // Attempt to normalize the cell to our left combined with this mark
+                            string combined = Contents [Row, Col - 1].Rune + rune.ToString ();
 
-                    Contents [Row, Col - 1].Attribute = CurrentAttribute;
-                    Contents [Row, Col - 1].IsDirty = true;
+                            // Normalize to Form C (Canonical Composition)
+                            string normalized = combined.Normalize (NormalizationForm.FormC);
+
+                            if (normalized.Length == 1)
+                            {
+                                // It normalized! We can just set the Cell to the left with the
+                                // normalized codepoint 
+                                Contents [Row, Col - 1].Rune = (Rune)normalized [0];
+
+                                // Ignore. Don't move to next column because we're already there
+                            }
+                            else
+                            {
+                                // It didn't normalize. Add it to the Cell to left's CM list
+                                Contents [Row, Col - 1].CombiningMarks.Add (rune);
+
+                                // Ignore. Don't move to next column (let the driver figure out what to do).
+                            }
+                        }
+
+                        Contents [Row, Col - 1].Attribute = CurrentAttribute;
+                        Contents [Row, Col - 1].IsDirty = true;
+                    }
+                    else
+                    {
+                        // Most drivers will render a combining mark at col 0 as the mark
+                        Contents [Row, Col].Rune = rune;
+                        Contents [Row, Col].Attribute = CurrentAttribute;
+                        Contents [Row, Col].IsDirty = true;
+                        Col++;
+                    }
                 }
                 else
                 {
-                    // Most drivers will render a combining mark at col 0 as the mark
-                    Contents [Row, Col].Rune = rune;
                     Contents [Row, Col].Attribute = CurrentAttribute;
                     Contents [Row, Col].IsDirty = true;
-                    Col++;
-                }
-            }
-            else
-            {
-                Contents [Row, Col].Attribute = CurrentAttribute;
-                Contents [Row, Col].IsDirty = true;
 
-                if (Col > 0)
-                {
-                    // Check if cell to left has a wide glyph
-                    if (Contents [Row, Col - 1].Rune.GetColumns () > 1)
+                    if (Col > 0)
                     {
-                        // Invalidate cell to left
-                        Contents [Row, Col - 1].Rune = Rune.ReplacementChar;
-                        Contents [Row, Col - 1].IsDirty = true;
+                        // Check if cell to left has a wide glyph
+                        if (Contents [Row, Col - 1].Rune.GetColumns () > 1)
+                        {
+                            // Invalidate cell to left
+                            Contents [Row, Col - 1].Rune = Rune.ReplacementChar;
+                            Contents [Row, Col - 1].IsDirty = true;
+                        }
                     }
-                }
 
-                if (runeWidth < 1)
-                {
-                    Contents [Row, Col].Rune = Rune.ReplacementChar;
-                }
-                else if (runeWidth == 1)
-                {
-                    Contents [Row, Col].Rune = rune;
-
-                    if (Col < Clip.Right - 1)
+                    if (runeWidth < 1)
                     {
-                        Contents [Row, Col + 1].IsDirty = true;
-                    }
-                }
-                else if (runeWidth == 2)
-                {
-                    if (Col == Clip.Right - 1)
-                    {
-                        // We're at the right edge of the clip, so we can't display a wide character.
-                        // TODO: Figure out if it is better to show a replacement character or ' '
                         Contents [Row, Col].Rune = Rune.ReplacementChar;
                     }
-                    else
+                    else if (runeWidth == 1)
                     {
                         Contents [Row, Col].Rune = rune;
 
                         if (Col < Clip.Right - 1)
                         {
-                            // Invalidate cell to right so that it doesn't get drawn
-                            // TODO: Figure out if it is better to show a replacement character or ' '
-                            Contents [Row, Col + 1].Rune = Rune.ReplacementChar;
                             Contents [Row, Col + 1].IsDirty = true;
                         }
                     }
-                }
-                else
-                {
-                    // This is a non-spacing character, so we don't need to do anything
-                    Contents [Row, Col].Rune = (Rune)' ';
-                    Contents [Row, Col].IsDirty = false;
-                }
+                    else if (runeWidth == 2)
+                    {
+                        if (Col == Clip.Right - 1)
+                        {
+                            // We're at the right edge of the clip, so we can't display a wide character.
+                            // TODO: Figure out if it is better to show a replacement character or ' '
+                            Contents [Row, Col].Rune = Rune.ReplacementChar;
+                        }
+                        else
+                        {
+                            Contents [Row, Col].Rune = rune;
 
-                _dirtyLines [Row] = true;
+                            if (Col < Clip.Right - 1)
+                            {
+                                // Invalidate cell to right so that it doesn't get drawn
+                                // TODO: Figure out if it is better to show a replacement character or ' '
+                                Contents [Row, Col + 1].Rune = Rune.ReplacementChar;
+                                Contents [Row, Col + 1].IsDirty = true;
+                            }
+                        }
+                    }
+                    else
+                    {
+                        // This is a non-spacing character, so we don't need to do anything
+                        Contents [Row, Col].Rune = (Rune)' ';
+                        Contents [Row, Col].IsDirty = false;
+                    }
+
+                    _dirtyLines! [Row] = true;
+                }
             }
         }
 
@@ -258,14 +266,17 @@ public abstract class ConsoleDriver
 
             if (validLocation && Col < Clip.Right)
             {
-                // This is a double-width character, and we are not at the end of the line.
-                // Col now points to the second column of the character. Ensure it doesn't
-                // Get rendered.
-                Contents [Row, Col].IsDirty = false;
-                Contents [Row, Col].Attribute = CurrentAttribute;
+                lock (Contents!)
+                {
+                    // This is a double-width character, and we are not at the end of the line.
+                    // Col now points to the second column of the character. Ensure it doesn't
+                    // Get rendered.
+                    Contents [Row, Col].IsDirty = false;
+                    Contents [Row, Col].Attribute = CurrentAttribute;
 
-                // TODO: Determine if we should wipe this out (for now now)
-                //Contents [Row, Col].Rune = (Rune)' ';
+                    // TODO: Determine if we should wipe this out (for now now)
+                    //Contents [Row, Col].Rune = (Rune)' ';
+                }
             }
 
             Col++;
@@ -332,7 +343,7 @@ public abstract class ConsoleDriver
     /// </summary>
     public void SetContentsAsDirty ()
     {
-        lock (Contents)
+        lock (Contents!)
         {
             for (var row = 0; row < Rows; row++)
             {
@@ -358,7 +369,7 @@ public abstract class ConsoleDriver
     public void FillRect (Rectangle rect, Rune rune = default)
     {
         rect = Rectangle.Intersect (rect, Clip);
-        lock (Contents)
+        lock (Contents!)
         {
             for (int r = rect.Y; r < rect.Y + rect.Height; r++)
             {

From 689c0cd93f6cc2892fe3cacaf56ed7a7be09c416 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Wed, 24 Jul 2024 14:37:23 -0600
Subject: [PATCH 21/33] Fixed nullable warnings 5

---
 Terminal.Gui/ConsoleDrivers/WindowsDriver.cs | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/Terminal.Gui/ConsoleDrivers/WindowsDriver.cs b/Terminal.Gui/ConsoleDrivers/WindowsDriver.cs
index 8ff127a4b..180745d9d 100644
--- a/Terminal.Gui/ConsoleDrivers/WindowsDriver.cs
+++ b/Terminal.Gui/ConsoleDrivers/WindowsDriver.cs
@@ -1266,18 +1266,18 @@ internal class WindowsDriver : ConsoleDriver
             return WinConsole?.WriteANSI (sb.ToString ()) ?? false;
         }
 
-        if (!(Col >= 0 && Row >= 0 && Col < Cols && Row < Rows))
-        {
-            GetCursorVisibility (out CursorVisibility cursorVisibility);
-            _cachedCursorVisibility = cursorVisibility;
-            SetCursorVisibility (CursorVisibility.Invisible);
+        //if (!(Col >= 0 && Row >= 0 && Col < Cols && Row < Rows))
+        //{
+        //    GetCursorVisibility (out CursorVisibility cursorVisibility);
+        //    _cachedCursorVisibility = cursorVisibility;
+        //    SetCursorVisibility (CursorVisibility.Invisible);
 
-            return false;
-        }
+        //    return false;
+        //}
 
-        SetCursorVisibility (_cachedCursorVisibility ?? CursorVisibility.Default);
+        //SetCursorVisibility (_cachedCursorVisibility ?? CursorVisibility.Default);
 
-        return _cachedCursorVisibility == CursorVisibility.Default;
+        //return _cachedCursorVisibility == CursorVisibility.Default;
     }
 
     #endregion Cursor Handling

From ff47aa29b9fe29e28c7bd52ed1aa718f0f87aa6a Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Wed, 24 Jul 2024 14:39:34 -0600
Subject: [PATCH 22/33] Fixed nullable warnings 6

---
 UnitTests/Views/ToplevelTests.cs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/UnitTests/Views/ToplevelTests.cs b/UnitTests/Views/ToplevelTests.cs
index 624da69ac..8688c5d4a 100644
--- a/UnitTests/Views/ToplevelTests.cs
+++ b/UnitTests/Views/ToplevelTests.cs
@@ -1049,12 +1049,12 @@ public partial class ToplevelTests (ITestOutputHelper output)
         Assert.False (subTop.IsLoaded);
         Assert.Equal (new (0, 0, 20, 10), view.Frame);
 
-        view.LayoutStarted += view_LayoutStarted;
+        view.LayoutStarted += ViewLayoutStarted;
 
-        void view_LayoutStarted (object sender, LayoutEventArgs e)
+        void ViewLayoutStarted (object sender, LayoutEventArgs e)
         {
             Assert.Equal (new (0, 0, 20, 10), view._needsDisplayRect);
-            view.LayoutStarted -= view_LayoutStarted;
+            view.LayoutStarted -= ViewLayoutStarted;
         }
 
         Application.Begin (top);

From 022050db730f7fc53d2dfb8e171e6da2ca82d137 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Wed, 24 Jul 2024 15:09:48 -0600
Subject: [PATCH 23/33] Fixed nullable warnings 7

---
 CommunityToolkitExample/Program.cs            |   2 +-
 .../Application/Application.Initialization.cs |  17 +-
 .../Application/Application.Keyboard.cs       |   4 +-
 Terminal.Gui/Application/Application.Mouse.cs |  22 +-
 .../Application/Application.Navigation.cs     | 197 ++++++++++++++++--
 Terminal.Gui/Application/Application.Run.cs   |   6 +-
 .../Application/Application.Toplevel.cs       | 142 -------------
 Terminal.Gui/Application/Application.cs       |   6 +-
 .../Application/MainLoopSyncContext.cs        |   2 +-
 Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs  |  10 +-
 Terminal.Gui/View/Adornment/ShadowView.cs     |   4 +-
 Terminal.Gui/View/EventArgs.cs                |   2 +-
 Terminal.Gui/View/Layout/Dim.cs               |   2 +-
 Terminal.Gui/View/Layout/DimView.cs           |   4 +-
 Terminal.Gui/View/Layout/PosView.cs           |   8 +-
 Terminal.Gui/View/View.cs                     |   2 +-
 Terminal.Gui/Views/TextValidateField.cs       |   8 +-
 Terminal.Gui/Views/Tile.cs                    |   2 +-
 UICatalog/Scenarios/Buttons.cs                |   4 +-
 UICatalog/Scenarios/ListViewWithSelection.cs  |   2 +-
 UICatalog/Scenarios/MenuBarScenario.cs        |   8 +-
 UICatalog/UICatalog.cs                        |   2 +-
 UnitTests/Application/ApplicationTests.cs     |  20 +-
 UnitTests/Application/KeyboardTests.cs        |   2 +-
 UnitTests/UICatalog/ScenarioTests.cs          |   2 +-
 UnitTests/View/DrawTests.cs                   |   8 +-
 UnitTests/Views/MenuBarTests.cs               |  19 +-
 27 files changed, 263 insertions(+), 244 deletions(-)

diff --git a/CommunityToolkitExample/Program.cs b/CommunityToolkitExample/Program.cs
index 0d4f21c30..a9ababfec 100644
--- a/CommunityToolkitExample/Program.cs
+++ b/CommunityToolkitExample/Program.cs
@@ -12,7 +12,7 @@ public static class Program
         Services = ConfigureServices ();
         Application.Init ();
         Application.Run (Services.GetRequiredService<LoginView> ());
-        Application.Top.Dispose();
+        Application.Top?.Dispose();
         Application.Shutdown ();
     }
 
diff --git a/Terminal.Gui/Application/Application.Initialization.cs b/Terminal.Gui/Application/Application.Initialization.cs
index 0d9b2caf5..37b34a358 100644
--- a/Terminal.Gui/Application/Application.Initialization.cs
+++ b/Terminal.Gui/Application/Application.Initialization.cs
@@ -38,8 +38,8 @@ public static partial class Application // Initialization (Init/Shutdown)
     [RequiresDynamicCode ("AOT")]
     public static void Init (ConsoleDriver? driver = null, string? driverName = null) { InternalInit (driver, driverName); }
 
-    internal static bool _initialized;
-    internal static int _mainThreadId = -1;
+    internal static bool IsInitialized { get; set; }
+    internal static int MainThreadId { get; set; } = -1;
 
     // INTERNAL function for initializing an app with a Toplevel factory object, driver, and mainloop.
     //
@@ -58,12 +58,12 @@ public static partial class Application // Initialization (Init/Shutdown)
         bool calledViaRunT = false
     )
     {
-        if (_initialized && driver is null)
+        if (IsInitialized && driver is null)
         {
             return;
         }
 
-        if (_initialized)
+        if (IsInitialized)
         {
             throw new InvalidOperationException ("Init has already been called and must be bracketed by Shutdown.");
         }
@@ -154,9 +154,9 @@ public static partial class Application // Initialization (Init/Shutdown)
         SynchronizationContext.SetSynchronizationContext (new MainLoopSyncContext ());
 
         SupportedCultures = GetSupportedCultures ();
-        _mainThreadId = Thread.CurrentThread.ManagedThreadId;
-        _initialized = true;
-        InitializedChanged?.Invoke (null, new (in _initialized));
+        MainThreadId = Thread.CurrentThread.ManagedThreadId;
+        bool init = IsInitialized = true;
+        InitializedChanged?.Invoke (null, new (init));
     }
 
     private static void Driver_SizeChanged (object? sender, SizeChangedEventArgs e) { OnSizeChanging (e); }
@@ -198,7 +198,8 @@ public static partial class Application // Initialization (Init/Shutdown)
         // TODO: Throw an exception if Init hasn't been called.
         ResetState ();
         PrintJsonErrors ();
-        InitializedChanged?.Invoke (null, new (in _initialized));
+        bool init = IsInitialized;
+        InitializedChanged?.Invoke (null, new (in init));
     }
 
     /// <summary>
diff --git a/Terminal.Gui/Application/Application.Keyboard.cs b/Terminal.Gui/Application/Application.Keyboard.cs
index 10419bf80..59c78a83e 100644
--- a/Terminal.Gui/Application/Application.Keyboard.cs
+++ b/Terminal.Gui/Application/Application.Keyboard.cs
@@ -110,7 +110,7 @@ public static partial class Application // Keyboard handling
     /// <returns><see langword="true"/> if the key was handled.</returns>
     public static bool OnKeyDown (Key keyEvent)
     {
-        if (!_initialized)
+        if (!IsInitialized)
         {
             return true;
         }
@@ -210,7 +210,7 @@ public static partial class Application // Keyboard handling
     /// <returns><see langword="true"/> if the key was handled.</returns>
     public static bool OnKeyUp (Key a)
     {
-        if (!_initialized)
+        if (!IsInitialized)
         {
             return true;
         }
diff --git a/Terminal.Gui/Application/Application.Mouse.cs b/Terminal.Gui/Application/Application.Mouse.cs
index 713e6375d..be7c38df6 100644
--- a/Terminal.Gui/Application/Application.Mouse.cs
+++ b/Terminal.Gui/Application/Application.Mouse.cs
@@ -64,7 +64,7 @@ public static partial class Application // Mouse handling
         }
     }
 
-    private static bool OnGrabbingMouse (View view)
+    private static bool OnGrabbingMouse (View? view)
     {
         if (view is null)
         {
@@ -77,7 +77,7 @@ public static partial class Application // Mouse handling
         return evArgs.Cancel;
     }
 
-    private static bool OnUnGrabbingMouse (View view)
+    private static bool OnUnGrabbingMouse (View? view)
     {
         if (view is null)
         {
@@ -90,7 +90,7 @@ public static partial class Application // Mouse handling
         return evArgs.Cancel;
     }
 
-    private static void OnGrabbedMouse (View view)
+    private static void OnGrabbedMouse (View? view)
     {
         if (view is null)
         {
@@ -100,7 +100,7 @@ public static partial class Application // Mouse handling
         GrabbedMouse?.Invoke (view, new (view));
     }
 
-    private static void OnUnGrabbedMouse (View view)
+    private static void OnUnGrabbedMouse (View? view)
     {
         if (view is null)
         {
@@ -113,7 +113,7 @@ public static partial class Application // Mouse handling
 #nullable enable
 
     // Used by OnMouseEvent to track the last view that was clicked on.
-    internal static View? _mouseEnteredView;
+    internal static View? MouseEnteredView { get; set; }
 
     /// <summary>Event fired when a mouse move or click occurs. Coordinates are screen relative.</summary>
     /// <remarks>
@@ -166,7 +166,7 @@ public static partial class Application // Mouse handling
             if ((MouseGrabView.Viewport with { Location = Point.Empty }).Contains (viewRelativeMouseEvent.Position) is false)
             {
                 // The mouse has moved outside the bounds of the view that grabbed the mouse
-                _mouseEnteredView?.NewMouseLeaveEvent (mouseEvent);
+                MouseEnteredView?.NewMouseLeaveEvent (mouseEvent);
             }
 
             //System.Diagnostics.Debug.WriteLine ($"{nme.Flags};{nme.X};{nme.Y};{mouseGrabView}");
@@ -242,16 +242,16 @@ public static partial class Application // Mouse handling
             return;
         }
 
-        if (_mouseEnteredView is null)
+        if (MouseEnteredView is null)
         {
-            _mouseEnteredView = view;
+            MouseEnteredView = view;
             view.NewMouseEnterEvent (me);
         }
-        else if (_mouseEnteredView != view)
+        else if (MouseEnteredView != view)
         {
-            _mouseEnteredView.NewMouseLeaveEvent (me);
+            MouseEnteredView.NewMouseLeaveEvent (me);
             view.NewMouseEnterEvent (me);
-            _mouseEnteredView = view;
+            MouseEnteredView = view;
         }
 
         if (!view.WantMousePositionReports && mouseEvent.Flags == MouseFlags.ReportMousePosition)
diff --git a/Terminal.Gui/Application/Application.Navigation.cs b/Terminal.Gui/Application/Application.Navigation.cs
index 0bbce67e6..d3f42fd64 100644
--- a/Terminal.Gui/Application/Application.Navigation.cs
+++ b/Terminal.Gui/Application/Application.Navigation.cs
@@ -1,3 +1,4 @@
+#nullable enable
 namespace Terminal.Gui;
 
 public static partial class Application
@@ -6,30 +7,32 @@ public static partial class Application
     ///     Gets the list of the Overlapped children which are not modal <see cref="Toplevel"/> from the
     ///     <see cref="OverlappedTop"/>.
     /// </summary>
-    public static List<Toplevel> OverlappedChildren
+    public static List<Toplevel>? OverlappedChildren
     {
         get
         {
             if (OverlappedTop is { })
             {
-                List<Toplevel> _overlappedChildren = new ();
+                List<Toplevel> overlappedChildren = new ();
 
-                foreach (Toplevel top in _topLevels)
+                lock (_topLevels)
                 {
-                    if (top != OverlappedTop && !top.Modal)
+                    foreach (Toplevel top in _topLevels)
                     {
-                        _overlappedChildren.Add (top);
+                        if (top != OverlappedTop && !top.Modal)
+                        {
+                            overlappedChildren.Add (top);
+                        }
                     }
                 }
 
-                return _overlappedChildren;
+                return overlappedChildren;
             }
 
             return null;
         }
     }
 
-#nullable enable
     /// <summary>
     ///     The <see cref="Toplevel"/> object used for the application on startup which
     ///     <see cref="Toplevel.IsOverlappedContainer"/> is true.
@@ -46,7 +49,6 @@ public static partial class Application
             return null;
         }
     }
-#nullable restore
 
     /// <summary>Brings the superview of the most focused overlapped view is on front.</summary>
     public static void BringOverlappedTopToFront ()
@@ -56,9 +58,9 @@ public static partial class Application
             return;
         }
 
-        View top = FindTopFromView (Top?.MostFocused);
+        View? top = FindTopFromView (Top?.MostFocused);
 
-        if (top is Toplevel && Top.Subviews.Count > 1 && Top.Subviews [^1] != top)
+        if (top is Toplevel && Top?.Subviews.Count > 1 && Top.Subviews [^1] != top)
         {
             Top.BringSubviewToFront (top);
         }
@@ -68,9 +70,9 @@ public static partial class Application
     /// <param name="type">The type.</param>
     /// <param name="exclude">The strings to exclude.</param>
     /// <returns>The matched view.</returns>
-    public static Toplevel GetTopOverlappedChild (Type type = null, string [] exclude = null)
+    public static Toplevel? GetTopOverlappedChild (Type? type = null, string []? exclude = null)
     {
-        if (OverlappedTop is null)
+        if (OverlappedChildren is null || OverlappedTop is null)
         {
             return null;
         }
@@ -118,7 +120,7 @@ public static partial class Application
     /// <summary>Move to the next Overlapped child from the <see cref="OverlappedTop"/>.</summary>
     public static void OverlappedMoveNext ()
     {
-        if (OverlappedTop is { } && !Current.Modal)
+        if (OverlappedTop is { } && !Current!.Modal)
         {
             lock (_topLevels)
             {
@@ -133,7 +135,7 @@ public static partial class Application
                     }
                     else if (isOverlapped && _topLevels.Peek () == OverlappedTop)
                     {
-                        MoveCurrent (Top);
+                        MoveCurrent (Top!);
 
                         break;
                     }
@@ -149,7 +151,7 @@ public static partial class Application
     /// <summary>Move to the previous Overlapped child from the <see cref="OverlappedTop"/>.</summary>
     public static void OverlappedMovePrevious ()
     {
-        if (OverlappedTop is { } && !Current.Modal)
+        if (OverlappedTop is { } && !Current!.Modal)
         {
             lock (_topLevels)
             {
@@ -164,7 +166,7 @@ public static partial class Application
                     }
                     else if (isOverlapped && _topLevels.Peek () == OverlappedTop)
                     {
-                        MoveCurrent (Top);
+                        MoveCurrent (Top!);
 
                         break;
                     }
@@ -184,13 +186,16 @@ public static partial class Application
             return false;
         }
 
-        foreach (Toplevel top in _topLevels)
+        lock (_topLevels)
         {
-            if (top != Current && top.Visible && (top.NeedsDisplay || top.SubViewNeedsDisplay || top.LayoutNeeded))
+            foreach (Toplevel top in _topLevels)
             {
-                OverlappedTop.SetSubViewNeedsDisplay ();
+                if (top != Current && top.Visible && (top.NeedsDisplay || top.SubViewNeedsDisplay || top.LayoutNeeded))
+                {
+                    OverlappedTop.SetSubViewNeedsDisplay ();
 
-                return true;
+                    return true;
+                }
             }
         }
 
@@ -208,4 +213,154 @@ public static partial class Application
 
         return false;
     }
-}
\ No newline at end of file
+
+    /// <summary>
+    ///     Finds the first Toplevel in the stack that is Visible and who's Frame contains the <paramref name="location"/>.
+    /// </summary>
+    /// <param name="start"></param>
+    /// <param name="location"></param>
+    /// <returns></returns>
+    private static Toplevel? FindDeepestTop (Toplevel start, in Point location)
+    {
+        if (!start.Frame.Contains (location))
+        {
+            return null;
+        }
+
+        lock (_topLevels)
+        {
+            if (_topLevels is not { Count: > 0 })
+            {
+                return start;
+            }
+
+            int rx = location.X - start.Frame.X;
+            int ry = location.Y - start.Frame.Y;
+
+            foreach (Toplevel t in _topLevels)
+            {
+                if (t == Current)
+                {
+                    continue;
+                }
+
+                if (t != start && t.Visible && t.Frame.Contains (rx, ry))
+                {
+                    start = t;
+
+                    break;
+                }
+            }
+        }
+
+        return start;
+    }
+
+    /// <summary>
+    ///     Given <paramref name="view"/>, returns the first Superview up the chain that is <see cref="Top"/>.
+    /// </summary>
+    private static View? FindTopFromView (View? view)
+    {
+        if (view is null)
+        {
+            return null;
+        }
+
+        View top = view.SuperView is { } && view.SuperView != Top
+                       ? view.SuperView
+                       : view;
+
+        while (top?.SuperView is { } && top?.SuperView != Top)
+        {
+            top = top!.SuperView;
+        }
+
+        return top;
+    }
+
+    /// <summary>
+    ///     If the <see cref="Current"/> is not the <paramref name="top"/> then <paramref name="top"/> is moved to the top of
+    ///     the Toplevel stack and made Current.
+    /// </summary>
+    /// <param name="top"></param>
+    /// <returns></returns>
+    private static bool MoveCurrent (Toplevel top)
+    {
+        // The Current is modal and the top is not modal Toplevel then
+        // the Current must be moved above the first not modal Toplevel.
+        if (OverlappedTop is { }
+            && top != OverlappedTop
+            && top != Current
+            && Current?.Modal == true
+            && !_topLevels.Peek ().Modal)
+        {
+            lock (_topLevels)
+            {
+                _topLevels.MoveTo (Current, 0, new ToplevelEqualityComparer ());
+            }
+
+            var index = 0;
+            Toplevel [] savedToplevels = _topLevels.ToArray ();
+
+            foreach (Toplevel t in savedToplevels)
+            {
+                if (!t!.Modal && t != Current && t != top && t != savedToplevels [index])
+                {
+                    lock (_topLevels)
+                    {
+                        _topLevels.MoveTo (top, index, new ToplevelEqualityComparer ());
+                    }
+                }
+
+                index++;
+            }
+
+            return false;
+        }
+
+        // The Current and the top are both not running Toplevel then
+        // the top must be moved above the first not running Toplevel.
+        if (OverlappedTop is { }
+            && top != OverlappedTop
+            && top != Current
+            && Current?.Running == false
+            && top?.Running == false)
+        {
+            lock (_topLevels)
+            {
+                _topLevels.MoveTo (Current, 0, new ToplevelEqualityComparer ());
+            }
+
+            var index = 0;
+
+            foreach (Toplevel t in _topLevels.ToArray ())
+            {
+                if (!t.Running && t != Current && index > 0)
+                {
+                    lock (_topLevels)
+                    {
+                        _topLevels.MoveTo (top, index - 1, new ToplevelEqualityComparer ());
+                    }
+                }
+
+                index++;
+            }
+
+            return false;
+        }
+
+        if ((OverlappedTop is { } && top?.Modal == true && _topLevels.Peek () != top)
+            || (OverlappedTop is { } && Current != OverlappedTop && Current?.Modal == false && top == OverlappedTop)
+            || (OverlappedTop is { } && Current?.Modal == false && top != Current)
+            || (OverlappedTop is { } && Current?.Modal == true && top == OverlappedTop))
+        {
+            lock (_topLevels)
+            {
+                _topLevels.MoveTo (top, 0, new ToplevelEqualityComparer ());
+                Current = top;
+            }
+        }
+
+        return true;
+    }
+}
diff --git a/Terminal.Gui/Application/Application.Run.cs b/Terminal.Gui/Application/Application.Run.cs
index 9a79af3d4..87bfde4c0 100644
--- a/Terminal.Gui/Application/Application.Run.cs
+++ b/Terminal.Gui/Application/Application.Run.cs
@@ -333,7 +333,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
     public static T Run<T> (Func<Exception, bool>? errorHandler = null, ConsoleDriver? driver = null)
         where T : Toplevel, new ()
     {
-        if (!_initialized)
+        if (!IsInitialized)
         {
             // Init() has NOT been called.
             InternalInit (driver, null, true);
@@ -388,7 +388,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
     {
         ArgumentNullException.ThrowIfNull (view);
 
-        if (_initialized)
+        if (IsInitialized)
         {
             if (Driver is null)
             {
@@ -824,7 +824,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
         }
         else
         {
-            if (_topLevels.Count > 1 && _topLevels.Peek () == OverlappedTop && OverlappedChildren.Any (t => t.Visible) is { })
+            if (_topLevels.Count > 1 && _topLevels.Peek () == OverlappedTop && OverlappedChildren?.Any (t => t.Visible) != null)
             {
                 OverlappedMoveNext ();
             }
diff --git a/Terminal.Gui/Application/Application.Toplevel.cs b/Terminal.Gui/Application/Application.Toplevel.cs
index d45360d64..a050e28f1 100644
--- a/Terminal.Gui/Application/Application.Toplevel.cs
+++ b/Terminal.Gui/Application/Application.Toplevel.cs
@@ -53,148 +53,6 @@ public static partial class Application // Toplevel handling
         }
     }
 
-    /// <summary>
-    ///    Finds the first Toplevel in the stack that is Visible and who's Frame contains the <paramref name="location"/>.
-    /// </summary>
-    /// <param name="start"></param>
-    /// <param name="location"></param>
-    /// <returns></returns>
-    private static Toplevel? FindDeepestTop (Toplevel start, in Point location)
-    {
-        if (!start.Frame.Contains (location))
-        {
-            return null;
-        }
-
-        if (_topLevels is { Count: > 0 })
-        {
-            int rx = location.X - start.Frame.X;
-            int ry = location.Y - start.Frame.Y;
-
-            foreach (Toplevel t in _topLevels)
-            {
-                if (t != Current)
-                {
-                    if (t != start && t.Visible && t.Frame.Contains (rx, ry))
-                    {
-                        start = t;
-
-                        break;
-                    }
-                }
-            }
-        }
-
-        return start;
-    }
-
-    /// <summary>
-    /// Given <paramref name="view"/>, returns the first Superview up the chain that is <see cref="Top"/>.
-    /// </summary>
-    private static View? FindTopFromView (View? view)
-    {
-        if (view is null)
-        {
-            return null;
-        }
-
-        View top = view.SuperView is { } && view.SuperView != Top
-                       ? view.SuperView
-                       : view;
-
-        while (top?.SuperView is { } && top?.SuperView != Top)
-        {
-            top = top!.SuperView;
-        }
-
-        return top;
-    }
-
-    /// <summary>
-    ///    If the <see cref="Current"/> is not the <paramref name="top"/> then <paramref name="top"/> is moved to the top of the Toplevel stack and made Current.
-    /// </summary>
-    /// <param name="top"></param>
-    /// <returns></returns>
-    private static bool MoveCurrent (Toplevel top)
-    {
-        // The Current is modal and the top is not modal Toplevel then
-        // the Current must be moved above the first not modal Toplevel.
-        if (OverlappedTop is { }
-            && top != OverlappedTop
-            && top != Current
-            && Current?.Modal == true
-            && !_topLevels.Peek ().Modal)
-        {
-            lock (_topLevels)
-            {
-                _topLevels.MoveTo (Current, 0, new ToplevelEqualityComparer ());
-            }
-
-            var index = 0;
-            Toplevel [] savedToplevels = _topLevels.ToArray ();
-
-            foreach (Toplevel t in savedToplevels)
-            {
-                if (!t!.Modal && t != Current && t != top && t != savedToplevels [index])
-                {
-                    lock (_topLevels)
-                    {
-                        _topLevels.MoveTo (top, index, new ToplevelEqualityComparer ());
-                    }
-                }
-
-                index++;
-            }
-
-            return false;
-        }
-
-        // The Current and the top are both not running Toplevel then
-        // the top must be moved above the first not running Toplevel.
-        if (OverlappedTop is { }
-            && top != OverlappedTop
-            && top != Current
-            && Current?.Running == false
-            && top?.Running == false)
-        {
-            lock (_topLevels)
-            {
-                _topLevels.MoveTo (Current, 0, new ToplevelEqualityComparer ());
-            }
-
-            var index = 0;
-
-            foreach (Toplevel t in _topLevels.ToArray ())
-            {
-                if (!t.Running && t != Current && index > 0)
-                {
-                    lock (_topLevels)
-                    {
-                        _topLevels.MoveTo (top, index - 1, new ToplevelEqualityComparer ());
-                    }
-                }
-
-                index++;
-            }
-
-            return false;
-        }
-
-        if ((OverlappedTop is { } && top?.Modal == true && _topLevels.Peek () != top)
-            || (OverlappedTop is { } && Current != OverlappedTop && Current?.Modal == false && top == OverlappedTop)
-            || (OverlappedTop is { } && Current?.Modal == false && top != Current)
-            || (OverlappedTop is { } && Current?.Modal == true && top == OverlappedTop))
-        {
-            lock (_topLevels)
-            {
-                _topLevels.MoveTo (top, 0, new ToplevelEqualityComparer ());
-                Current = top;
-            }
-        }
-
-        return true;
-    }
-
     /// <summary>Invoked when the terminal's size changed. The new size of the terminal is provided.</summary>
     /// <remarks>
     ///     Event handlers can set <see cref="SizeChangedEventArgs.Cancel"/> to <see langword="true"/> to prevent
diff --git a/Terminal.Gui/Application/Application.cs b/Terminal.Gui/Application/Application.cs
index 76c05922b..75fbd7191 100644
--- a/Terminal.Gui/Application/Application.cs
+++ b/Terminal.Gui/Application/Application.cs
@@ -84,7 +84,7 @@ public static partial class Application
         // MainLoop stuff
         MainLoop?.Dispose ();
         MainLoop = null;
-        _mainThreadId = -1;
+        MainThreadId = -1;
         Iteration = null;
         EndAfterFirstIteration = false;
 
@@ -108,10 +108,10 @@ public static partial class Application
         NotifyNewRunState = null;
         NotifyStopRunState = null;
         MouseGrabView = null;
-        _initialized = false;
+        IsInitialized = false;
 
         // Mouse
-        _mouseEnteredView = null;
+        MouseEnteredView = null;
         WantContinuousButtonPressedView = null;
         MouseEvent = null;
         GrabbedMouse = null;
diff --git a/Terminal.Gui/Application/MainLoopSyncContext.cs b/Terminal.Gui/Application/MainLoopSyncContext.cs
index 5290a2076..749c76268 100644
--- a/Terminal.Gui/Application/MainLoopSyncContext.cs
+++ b/Terminal.Gui/Application/MainLoopSyncContext.cs
@@ -23,7 +23,7 @@ internal sealed class MainLoopSyncContext : SynchronizationContext
     //_mainLoop.Driver.Wakeup ();
     public override void Send (SendOrPostCallback d, object state)
     {
-        if (Thread.CurrentThread.ManagedThreadId == Application._mainThreadId)
+        if (Thread.CurrentThread.ManagedThreadId == Application.MainThreadId)
         {
             d (state);
         }
diff --git a/Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs b/Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs
index 5e9a7dad3..e99521d1e 100644
--- a/Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs
+++ b/Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs
@@ -351,7 +351,7 @@ public abstract class ConsoleDriver
                 {
                     Contents [row, c].IsDirty = true;
                 }
-                _dirtyLines [row] = true;
+                _dirtyLines! [row] = true;
             }
         }
     }
@@ -380,7 +380,7 @@ public abstract class ConsoleDriver
                         Rune = (rune != default ? rune : (Rune)' '),
                         Attribute = CurrentAttribute, IsDirty = true
                     };
-                    _dirtyLines [r] = true;
+                    _dirtyLines! [r] = true;
                 }
             }
         }
@@ -561,7 +561,7 @@ public abstract class ConsoleDriver
     #region Mouse and Keyboard
 
     /// <summary>Event fired when a key is pressed down. This is a precursor to <see cref="KeyUp"/>.</summary>
-    public event EventHandler<Key> KeyDown;
+    public event EventHandler<Key>? KeyDown;
 
     /// <summary>
     ///     Called when a key is pressed down. Fires the <see cref="KeyDown"/> event. This is a precursor to
@@ -575,7 +575,7 @@ public abstract class ConsoleDriver
     ///     Drivers that do not support key release events will fire this event after <see cref="KeyDown"/> processing is
     ///     complete.
     /// </remarks>
-    public event EventHandler<Key> KeyUp;
+    public event EventHandler<Key>? KeyUp;
 
     /// <summary>Called when a key is released. Fires the <see cref="KeyUp"/> event.</summary>
     /// <remarks>
@@ -586,7 +586,7 @@ public abstract class ConsoleDriver
     public void OnKeyUp (Key a) { KeyUp?.Invoke (this, a); }
 
     /// <summary>Event fired when a mouse event occurs.</summary>
-    public event EventHandler<MouseEvent> MouseEvent;
+    public event EventHandler<MouseEvent>? MouseEvent;
 
     /// <summary>Called when a mouse event occurs. Fires the <see cref="MouseEvent"/> event.</summary>
     /// <param name="a"></param>
diff --git a/Terminal.Gui/View/Adornment/ShadowView.cs b/Terminal.Gui/View/Adornment/ShadowView.cs
index ad06dc754..e6009759a 100644
--- a/Terminal.Gui/View/Adornment/ShadowView.cs
+++ b/Terminal.Gui/View/Adornment/ShadowView.cs
@@ -109,7 +109,7 @@ internal class ShadowView : View
         for (int i = screen.X; i < screen.X + screen.Width - 1; i++)
         {
             Driver.Move (i, screen.Y);
-            Driver.AddRune (Driver.Contents [screen.Y, i].Rune);
+            Driver.AddRune (Driver.Contents! [screen.Y, i].Rune);
         }
     }
 
@@ -133,7 +133,7 @@ internal class ShadowView : View
         for (int i = screen.Y; i < screen.Y + viewport.Height; i++)
         {
             Driver.Move (screen.X, i);
-            Driver.AddRune (Driver.Contents [i, screen.X].Rune);
+            Driver.AddRune (Driver.Contents! [i, screen.X].Rune);
         }
     }
 }
diff --git a/Terminal.Gui/View/EventArgs.cs b/Terminal.Gui/View/EventArgs.cs
index 03309a0f5..1de2347c6 100644
--- a/Terminal.Gui/View/EventArgs.cs
+++ b/Terminal.Gui/View/EventArgs.cs
@@ -11,7 +11,7 @@ public class EventArgs<T> : EventArgs where T : notnull
     /// <summary>Initializes a new instance of the <see cref="EventArgs{T}"/> class.</summary>
     /// <param name="currentValue">The current value of the property.</param>
     /// <typeparam name="T">The type of the value.</typeparam>
-    public EventArgs (ref readonly T currentValue) { CurrentValue = currentValue; }
+    public EventArgs (in T currentValue) { CurrentValue = currentValue; }
 
     /// <summary>The current value of the property.</summary>
     public T CurrentValue { get; }
diff --git a/Terminal.Gui/View/Layout/Dim.cs b/Terminal.Gui/View/Layout/Dim.cs
index 3102d5d3c..f6f50f798 100644
--- a/Terminal.Gui/View/Layout/Dim.cs
+++ b/Terminal.Gui/View/Layout/Dim.cs
@@ -257,7 +257,7 @@ public abstract class Dim
         }
 
         var newDim = new DimCombine (AddOrSubtract.Subtract, left, right);
-        (left as DimView)?.Target.SetNeedsLayout ();
+        (left as DimView)?.Target?.SetNeedsLayout ();
 
         return newDim;
     }
diff --git a/Terminal.Gui/View/Layout/DimView.cs b/Terminal.Gui/View/Layout/DimView.cs
index e95efd4fb..7a7568a95 100644
--- a/Terminal.Gui/View/Layout/DimView.cs
+++ b/Terminal.Gui/View/Layout/DimView.cs
@@ -52,8 +52,8 @@ public class DimView : Dim
     {
         return Dimension switch
                {
-                   Dimension.Height => Target.Frame.Height,
-                   Dimension.Width => Target.Frame.Width,
+                   Dimension.Height => Target!.Frame.Height,
+                   Dimension.Width => Target!.Frame.Width,
                    _ => 0
                };
     }
diff --git a/Terminal.Gui/View/Layout/PosView.cs b/Terminal.Gui/View/Layout/PosView.cs
index 8ceba980f..a46f6898a 100644
--- a/Terminal.Gui/View/Layout/PosView.cs
+++ b/Terminal.Gui/View/Layout/PosView.cs
@@ -47,10 +47,10 @@ public class PosView (View? view, Side side) : Pos
     {
         return Side switch
                {
-                   Side.Left => Target.Frame.X,
-                   Side.Top => Target.Frame.Y,
-                   Side.Right => Target.Frame.Right,
-                   Side.Bottom => Target.Frame.Bottom,
+                   Side.Left => Target!.Frame.X,
+                   Side.Top => Target!.Frame.Y,
+                   Side.Right => Target!.Frame.Right,
+                   Side.Bottom => Target!.Frame.Bottom,
                    _ => 0
                };
     }
diff --git a/Terminal.Gui/View/View.cs b/Terminal.Gui/View/View.cs
index 68eb1853f..d340a5aa4 100644
--- a/Terminal.Gui/View/View.cs
+++ b/Terminal.Gui/View/View.cs
@@ -490,7 +490,7 @@ public partial class View : Responder, ISupportInitializeNotification
     /// <summary>Called when the <see cref="View.Title"/> has been changed. Invokes the <see cref="TitleChanged"/> event.</summary>
     protected void OnTitleChanged ()
     {
-        TitleChanged?.Invoke (this, new (ref _title));
+        TitleChanged?.Invoke (this, new (in _title));
     }
 
     /// <summary>
diff --git a/Terminal.Gui/Views/TextValidateField.cs b/Terminal.Gui/Views/TextValidateField.cs
index 045f6df3f..b0df130b3 100644
--- a/Terminal.Gui/Views/TextValidateField.cs
+++ b/Terminal.Gui/Views/TextValidateField.cs
@@ -206,7 +206,7 @@ namespace Terminal.Gui
 
                 if (result)
                 {
-                    OnTextChanged (new EventArgs<string> (ref oldValue));
+                    OnTextChanged (new EventArgs<string> (in oldValue));
                 }
 
                 return result;
@@ -220,7 +220,7 @@ namespace Terminal.Gui
 
                 if (result)
                 {
-                    OnTextChanged (new EventArgs<string> (ref oldValue));
+                    OnTextChanged (new EventArgs<string> (in oldValue));
                 }
 
                 return result;
@@ -333,7 +333,7 @@ namespace Terminal.Gui
                 {
                     string oldValue = Text;
                     _text.RemoveAt (pos);
-                    OnTextChanged (new EventArgs<string> (ref oldValue));
+                    OnTextChanged (new EventArgs<string> (in oldValue));
                 }
 
                 return true;
@@ -349,7 +349,7 @@ namespace Terminal.Gui
                 {
                     string oldValue = Text;
                     _text.Insert (pos, (Rune)ch);
-                    OnTextChanged (new EventArgs<string> (ref oldValue));
+                    OnTextChanged (new EventArgs<string> (in oldValue));
 
                     return true;
                 }
diff --git a/Terminal.Gui/Views/Tile.cs b/Terminal.Gui/Views/Tile.cs
index ebc4b9f59..5224db8b4 100644
--- a/Terminal.Gui/Views/Tile.cs
+++ b/Terminal.Gui/Views/Tile.cs
@@ -62,7 +62,7 @@ public class Tile
     /// <param name="newTitle">The new <see cref="Title"/> to be replaced.</param>
     public virtual void OnTitleChanged (string oldTitle, string newTitle)
     {
-        var args = new EventArgs<string> (ref newTitle);
+        var args = new EventArgs<string> (in newTitle);
         TitleChanged?.Invoke (this, args);
     }
 
diff --git a/UICatalog/Scenarios/Buttons.cs b/UICatalog/Scenarios/Buttons.cs
index aab815a96..2ea67238e 100644
--- a/UICatalog/Scenarios/Buttons.cs
+++ b/UICatalog/Scenarios/Buttons.cs
@@ -527,8 +527,8 @@ public class Buttons : Scenario
                 }
 
                 _value = value;
-                _number.Text = _value.ToString ();
-                ValueChanged?.Invoke (this, new (ref _value));
+                _number.Text = _value.ToString ()!;
+                ValueChanged?.Invoke (this, new (in _value));
             }
         }
 
diff --git a/UICatalog/Scenarios/ListViewWithSelection.cs b/UICatalog/Scenarios/ListViewWithSelection.cs
index afcd8a542..27e1bf5d2 100644
--- a/UICatalog/Scenarios/ListViewWithSelection.cs
+++ b/UICatalog/Scenarios/ListViewWithSelection.cs
@@ -205,7 +205,7 @@ public class ListViewWithSelection : Scenario
 
         /// <inheritdoc />
         public event NotifyCollectionChangedEventHandler CollectionChanged;
-        public int Count => Scenarios != null ? Scenarios.Count : 0;
+        public int Count => Scenarios?.Count ?? 0;
         public int Length { get; private set; }
         public bool SuspendCollectionChangedEvent { get => throw new System.NotImplementedException (); set => throw new System.NotImplementedException (); }
 
diff --git a/UICatalog/Scenarios/MenuBarScenario.cs b/UICatalog/Scenarios/MenuBarScenario.cs
index 73c767f79..b9c6bee67 100644
--- a/UICatalog/Scenarios/MenuBarScenario.cs
+++ b/UICatalog/Scenarios/MenuBarScenario.cs
@@ -1,5 +1,6 @@
 using System;
 using Terminal.Gui;
+using static System.Runtime.InteropServices.JavaScript.JSType;
 
 namespace UICatalog.Scenarios;
 
@@ -64,14 +65,17 @@ public class MenuBarScenario : Scenario
         menuBar.Key = KeyCode.F9;
         menuBar.Title = "TestMenuBar";
 
-        bool fnAction (string s)
+        bool FnAction (string s)
         {
             _lastAction.Text = s;
 
             return true;
         }
+        
+        // Declare a variable for the function
+        Func<string, bool> fnActionVariable = FnAction;
 
-        menuBar.EnableForDesign ((Func<string, bool>)fnAction);
+        menuBar.EnableForDesign (ref fnActionVariable);
 
         menuBar.MenuOpening += (s, e) =>
                                {
diff --git a/UICatalog/UICatalog.cs b/UICatalog/UICatalog.cs
index a2cc9a474..a9014d017 100644
--- a/UICatalog/UICatalog.cs
+++ b/UICatalog/UICatalog.cs
@@ -104,7 +104,7 @@ internal class UICatalogApp
         // If no driver is provided, the default driver is used.
         Option<string> driverOption = new Option<string> ("--driver", "The ConsoleDriver to use.").FromAmong (
              Application.GetDriverTypes ()
-                        .Select (d => d.Name)
+                        .Select (d => d!.Name)
                         .ToArray ()
             );
 
diff --git a/UnitTests/Application/ApplicationTests.cs b/UnitTests/Application/ApplicationTests.cs
index f8f1f8029..c600254a2 100644
--- a/UnitTests/Application/ApplicationTests.cs
+++ b/UnitTests/Application/ApplicationTests.cs
@@ -162,7 +162,7 @@ public class ApplicationTests
         // Set some values
 
         Application.Init (driverName: driverType.Name);
-        Application._initialized = true;
+        Application.IsInitialized = true;
 
         // Reset
         Application.ResetState ();
@@ -191,12 +191,12 @@ public class ApplicationTests
             Assert.Null (Application.OverlappedTop);
 
             // Internal properties
-            Assert.False (Application._initialized);
+            Assert.False (Application.IsInitialized);
             Assert.Equal (Application.GetSupportedCultures (), Application.SupportedCultures);
             Assert.False (Application._forceFakeConsole);
-            Assert.Equal (-1, Application._mainThreadId);
+            Assert.Equal (-1, Application.MainThreadId);
             Assert.Empty (Application._topLevels);
-            Assert.Null (Application._mouseEnteredView);
+            Assert.Null (Application.MouseEnteredView);
 
             // Keyboard
             Assert.Empty (Application.GetViewKeyBindings ());
@@ -218,12 +218,12 @@ public class ApplicationTests
         CheckReset ();
 
         // Set the values that can be set
-        Application._initialized = true;
+        Application.IsInitialized = true;
         Application._forceFakeConsole = true;
-        Application._mainThreadId = 1;
+        Application.MainThreadId = 1;
 
         //Application._topLevels = new List<Toplevel> ();
-        Application._mouseEnteredView = new ();
+        Application.MouseEnteredView = new ();
 
         //Application.SupportedCultures = new List<CultureInfo> ();
         Application.Force16Colors = true;
@@ -237,7 +237,7 @@ public class ApplicationTests
 
         //Application.OverlappedChildren = new List<View> ();
         //Application.OverlappedTop = 
-        Application._mouseEnteredView = new ();
+        Application.MouseEnteredView = new ();
 
         //Application.WantContinuousButtonPressedView = new View ();
 
@@ -413,7 +413,7 @@ public class ApplicationTests
     [AutoInitShutdown]
     public void Internal_Properties_Correct ()
     {
-        Assert.True (Application._initialized);
+        Assert.True (Application.IsInitialized);
         Assert.Null (Application.Top);
         RunState rs = Application.Begin (new ());
         Assert.Equal (Application.Top, rs.Toplevel);
@@ -1206,7 +1206,7 @@ public class ApplicationTests
             Thread.Sleep ((int)timeoutTime / 10);
 
             // Worst case scenario - something went wrong
-            if (Application._initialized && iteration > 25)
+            if (Application.IsInitialized && iteration > 25)
             {
                 _output.WriteLine ($"Too many iterations ({iteration}): Calling Application.RequestStop.");
                 Application.RequestStop ();
diff --git a/UnitTests/Application/KeyboardTests.cs b/UnitTests/Application/KeyboardTests.cs
index 4dfb5b11a..a61519037 100644
--- a/UnitTests/Application/KeyboardTests.cs
+++ b/UnitTests/Application/KeyboardTests.cs
@@ -169,7 +169,7 @@ public class KeyboardTests
             _output.WriteLine ("Iteration: {0}", iteration);
             iteration++;
             Assert.True (iteration < 2, "Too many iterations, something is wrong.");
-            if (Application._initialized)
+            if (Application.IsInitialized)
             {
                 _output.WriteLine ("  Pressing QuitKey");
                 Application.OnKeyDown (Application.QuitKey);
diff --git a/UnitTests/UICatalog/ScenarioTests.cs b/UnitTests/UICatalog/ScenarioTests.cs
index 22a9e25c6..5e0dc2a5c 100644
--- a/UnitTests/UICatalog/ScenarioTests.cs
+++ b/UnitTests/UICatalog/ScenarioTests.cs
@@ -115,7 +115,7 @@ public class ScenarioTests : TestsAllViews
 
         void OnApplicationOnIteration (object s, IterationEventArgs a)
         {
-            if (Application._initialized)
+            if (Application.IsInitialized)
             {
                 // Press QuitKey 
                 //_output.WriteLine ($"Forcing Quit with {Application.QuitKey}");
diff --git a/UnitTests/View/DrawTests.cs b/UnitTests/View/DrawTests.cs
index 52b4659f8..19ed80383 100644
--- a/UnitTests/View/DrawTests.cs
+++ b/UnitTests/View/DrawTests.cs
@@ -48,16 +48,16 @@ public class DrawTests (ITestOutputHelper _output)
         view.Draw ();
 
         // Only valid location w/in Viewport is 0, 0 (view) - 2, 2 (screen)
-        Assert.Equal ((Rune)' ', Application.Driver?.Contents [2, 2].Rune);
+        Assert.Equal ((Rune)' ', Application.Driver?.Contents! [2, 2].Rune);
 
         view.AddRune (0, 0, Rune.ReplacementChar);
-        Assert.Equal (Rune.ReplacementChar, Application.Driver?.Contents [2, 2].Rune);
+        Assert.Equal (Rune.ReplacementChar, Application.Driver?.Contents! [2, 2].Rune);
 
         view.AddRune (-1, -1, Rune.ReplacementChar);
-        Assert.Equal ((Rune)'M', Application.Driver?.Contents [1, 1].Rune);
+        Assert.Equal ((Rune)'M', Application.Driver?.Contents! [1, 1].Rune);
 
         view.AddRune (1, 1, Rune.ReplacementChar);
-        Assert.Equal ((Rune)'M', Application.Driver?.Contents [3, 3].Rune);
+        Assert.Equal ((Rune)'M', Application.Driver?.Contents! [3, 3].Rune);
 
         View.Diagnostics = ViewDiagnosticFlags.Off;
     }
diff --git a/UnitTests/Views/MenuBarTests.cs b/UnitTests/Views/MenuBarTests.cs
index 6f9de4683..76598902c 100644
--- a/UnitTests/Views/MenuBarTests.cs
+++ b/UnitTests/Views/MenuBarTests.cs
@@ -1301,15 +1301,16 @@ wo
 
         var menu = new MenuBar ();
 
-        menu.EnableForDesign (
-                              new Func<object, bool> (
-                                                      s =>
-                                                      {
-                                                          miAction = s as string;
+        bool FnAction (string s)
+        {
+            miAction = s;
 
-                                                          return true;
-                                                      })
-                             );
+            return true;
+        }
+        // Declare a variable for the function
+        Func<string, bool> fnActionVariable = FnAction;
+
+        menu.EnableForDesign (ref fnActionVariable);
 
         menu.Key = KeyCode.F9;
         menu.MenuOpening += (s, e) => mbiCurrent = e.CurrentMenu;
@@ -1329,7 +1330,7 @@ wo
         foreach (KeyCode key in keys)
         {
             Assert.True (top.NewKeyDownEvent (new (key)));
-            Application.MainLoop.RunIteration ();
+            Application.MainLoop!.RunIteration ();
         }
 
         Assert.Equal (expectedAction, miAction);

From f37ec5e04f314385859d8c00285283d24a4b1c96 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Wed, 24 Jul 2024 15:42:04 -0600
Subject: [PATCH 24/33] Moved Overlapped stuff to ApplicationOverlap static
 class. Fixed nullable warnings.

---
 .../Application/Application .Screen.cs        |  45 ++
 .../Application/Application.Initialization.cs |   8 +-
 .../Application/Application.Keyboard.cs       |  14 +-
 Terminal.Gui/Application/Application.Mouse.cs |  12 +-
 .../Application/Application.Navigation.cs     | 450 +++++------------
 .../Application/Application.Overlapped.cs     | 465 +++++++++++++-----
 Terminal.Gui/Application/Application.Run.cs   | 116 ++---
 .../Application/Application.Toplevel.cs       |  57 +--
 Terminal.Gui/Application/Application.cs       |   4 +-
 Terminal.Gui/View/Adornment/Border.cs         |   2 +-
 Terminal.Gui/View/ViewSubViews.cs             |   4 +-
 Terminal.Gui/Views/TileView.cs                |   2 +-
 Terminal.Gui/Views/Toplevel.cs                |  10 +-
 Terminal.Gui/Views/ToplevelOverlapped.cs      |   2 +-
 .../Scenarios/BackgroundWorkerCollection.cs   |  26 +-
 UnitTests/Application/ApplicationTests.cs     |  24 +-
 UnitTests/Views/OverlappedTests.cs            | 269 +++++-----
 17 files changed, 758 insertions(+), 752 deletions(-)
 create mode 100644 Terminal.Gui/Application/Application .Screen.cs

diff --git a/Terminal.Gui/Application/Application .Screen.cs b/Terminal.Gui/Application/Application .Screen.cs
new file mode 100644
index 000000000..7770ae13c
--- /dev/null
+++ b/Terminal.Gui/Application/Application .Screen.cs	
@@ -0,0 +1,45 @@
+#nullable enable
+namespace Terminal.Gui;
+
+public static partial class Application // Screen related stuff
+{
+    /// <summary>Invoked when the terminal's size changed. The new size of the terminal is provided.</summary>
+    /// <remarks>
+    ///     Event handlers can set <see cref="SizeChangedEventArgs.Cancel"/> to <see langword="true"/> to prevent
+    ///     <see cref="Application"/> from changing it's size to match the new terminal size.
+    /// </remarks>
+    public static event EventHandler<SizeChangedEventArgs>? SizeChanging;
+
+    /// <summary>
+    ///     Called when the application's size changes. Sets the size of all <see cref="Toplevel"/>s and fires the
+    ///     <see cref="SizeChanging"/> event.
+    /// </summary>
+    /// <param name="args">The new size.</param>
+    /// <returns><see lanword="true"/>if the size was changed.</returns>
+    public static bool OnSizeChanging (SizeChangedEventArgs args)
+    {
+        SizeChanging?.Invoke (null, args);
+
+        if (args.Cancel || args.Size is null)
+        {
+            return false;
+        }
+
+        foreach (Toplevel t in TopLevels)
+        {
+            t.SetRelativeLayout (args.Size.Value);
+            t.LayoutSubviews ();
+            t.PositionToplevels ();
+            t.OnSizeChanging (new (args.Size));
+
+            if (PositionCursor (t))
+            {
+                Driver?.UpdateCursor ();
+            }
+        }
+
+        Refresh ();
+
+        return true;
+    }
+}
diff --git a/Terminal.Gui/Application/Application.Initialization.cs b/Terminal.Gui/Application/Application.Initialization.cs
index 37b34a358..a2aacaab5 100644
--- a/Terminal.Gui/Application/Application.Initialization.cs
+++ b/Terminal.Gui/Application/Application.Initialization.cs
@@ -146,10 +146,10 @@ public static partial class Application // Initialization (Init/Shutdown)
                                                 );
         }
 
-        Driver.SizeChanged += (s, args) => OnSizeChanging (args);
-        Driver.KeyDown += (s, args) => OnKeyDown (args);
-        Driver.KeyUp += (s, args) => OnKeyUp (args);
-        Driver.MouseEvent += (s, args) => OnMouseEvent (args);
+        Driver.SizeChanged += Driver_SizeChanged;
+        Driver.KeyDown += Driver_KeyDown;
+        Driver.KeyUp += Driver_KeyUp;
+        Driver.MouseEvent += Driver_MouseEvent;
 
         SynchronizationContext.SetSynchronizationContext (new MainLoopSyncContext ());
 
diff --git a/Terminal.Gui/Application/Application.Keyboard.cs b/Terminal.Gui/Application/Application.Keyboard.cs
index 59c78a83e..d26dcd432 100644
--- a/Terminal.Gui/Application/Application.Keyboard.cs
+++ b/Terminal.Gui/Application/Application.Keyboard.cs
@@ -122,7 +122,7 @@ public static partial class Application // Keyboard handling
             return true;
         }
 
-        foreach (Toplevel topLevel in _topLevels.ToList ())
+        foreach (Toplevel topLevel in TopLevels.ToList ())
         {
             if (topLevel.NewKeyDownEvent (keyEvent))
             {
@@ -222,7 +222,7 @@ public static partial class Application // Keyboard handling
             return true;
         }
 
-        foreach (Toplevel topLevel in _topLevels.ToList ())
+        foreach (Toplevel topLevel in TopLevels.ToList ())
         {
             if (topLevel.NewKeyUpEvent (a))
             {
@@ -302,7 +302,7 @@ public static partial class Application // Keyboard handling
                     Command.QuitToplevel,  // TODO: IRunnable: Rename to Command.Quit to make more generic.
                     () =>
                     {
-                        if (OverlappedTop is { })
+                        if (ApplicationOverlapped.OverlappedTop is { })
                         {
                             RequestStop (Current!);
                         }
@@ -330,7 +330,7 @@ public static partial class Application // Keyboard handling
                     () =>
                     {
                         // TODO: Move this method to Application.Navigation.cs
-                        ViewNavigation.MoveNextView ();
+                        ApplicationNavigation.MoveNextView ();
 
                         return true;
                     }
@@ -341,7 +341,7 @@ public static partial class Application // Keyboard handling
                     () =>
                     {
                         // TODO: Move this method to Application.Navigation.cs
-                        ViewNavigation.MovePreviousView ();
+                        ApplicationNavigation.MovePreviousView ();
 
                         return true;
                     }
@@ -352,7 +352,7 @@ public static partial class Application // Keyboard handling
                     () =>
                     {
                         // TODO: Move this method to Application.Navigation.cs
-                        ViewNavigation.MoveNextViewOrTop ();
+                        ApplicationNavigation.MoveNextViewOrTop ();
 
                         return true;
                     }
@@ -363,7 +363,7 @@ public static partial class Application // Keyboard handling
                     () =>
                     {
                         // TODO: Move this method to Application.Navigation.cs
-                        ViewNavigation.MovePreviousViewOrTop ();
+                        ApplicationNavigation.MovePreviousViewOrTop ();
 
                         return true;
                     }
diff --git a/Terminal.Gui/Application/Application.Mouse.cs b/Terminal.Gui/Application/Application.Mouse.cs
index be7c38df6..2c497b761 100644
--- a/Terminal.Gui/Application/Application.Mouse.cs
+++ b/Terminal.Gui/Application/Application.Mouse.cs
@@ -187,20 +187,20 @@ public static partial class Application // Mouse handling
 
         if (view is not Adornment)
         {
-            if ((view is null || view == OverlappedTop)
+            if ((view is null || view == ApplicationOverlapped.OverlappedTop)
                 && Current is { Modal: false }
-                && OverlappedTop != null
+                && ApplicationOverlapped.OverlappedTop != null
                 && mouseEvent.Flags != MouseFlags.ReportMousePosition
                 && mouseEvent.Flags != 0)
             {
                 // This occurs when there are multiple overlapped "tops"
                 // E.g. "Mdi" - in the Background Worker Scenario
-                View? top = FindDeepestTop (Top!, mouseEvent.Position);
+                View? top = ApplicationOverlapped.FindDeepestTop (Top!, mouseEvent.Position);
                 view = View.FindDeepestView (top, mouseEvent.Position);
 
-                if (view is { } && view != OverlappedTop && top != Current && top is { })
+                if (view is { } && view != ApplicationOverlapped.OverlappedTop && top != Current && top is { })
                 {
-                    MoveCurrent ((Toplevel)top);
+                    ApplicationOverlapped.MoveCurrent ((Toplevel)top);
                 }
             }
         }
@@ -295,7 +295,7 @@ public static partial class Application // Mouse handling
             };
         }
 
-        BringOverlappedTopToFront ();
+        ApplicationOverlapped.BringOverlappedTopToFront ();
     }
 
     #endregion Mouse handling
diff --git a/Terminal.Gui/Application/Application.Navigation.cs b/Terminal.Gui/Application/Application.Navigation.cs
index d3f42fd64..44bc6e99a 100644
--- a/Terminal.Gui/Application/Application.Navigation.cs
+++ b/Terminal.Gui/Application/Application.Navigation.cs
@@ -1,366 +1,162 @@
 #nullable enable
 namespace Terminal.Gui;
 
-public static partial class Application
+internal static class ApplicationNavigation
 {
     /// <summary>
-    ///     Gets the list of the Overlapped children which are not modal <see cref="Toplevel"/> from the
-    ///     <see cref="OverlappedTop"/>.
+    ///    Gets the deepest focused subview of the specified <paramref name="view"/>.
     /// </summary>
-    public static List<Toplevel>? OverlappedChildren
-    {
-        get
-        {
-            if (OverlappedTop is { })
-            {
-                List<Toplevel> overlappedChildren = new ();
-
-                lock (_topLevels)
-                {
-                    foreach (Toplevel top in _topLevels)
-                    {
-                        if (top != OverlappedTop && !top.Modal)
-                        {
-                            overlappedChildren.Add (top);
-                        }
-                    }
-                }
-
-                return overlappedChildren;
-            }
-
-            return null;
-        }
-    }
-
-    /// <summary>
-    ///     The <see cref="Toplevel"/> object used for the application on startup which
-    ///     <see cref="Toplevel.IsOverlappedContainer"/> is true.
-    /// </summary>
-    public static Toplevel? OverlappedTop
-    {
-        get
-        {
-            if (Top is { IsOverlappedContainer: true })
-            {
-                return Top;
-            }
-
-            return null;
-        }
-    }
-
-    /// <summary>Brings the superview of the most focused overlapped view is on front.</summary>
-    public static void BringOverlappedTopToFront ()
-    {
-        if (OverlappedTop is { })
-        {
-            return;
-        }
-
-        View? top = FindTopFromView (Top?.MostFocused);
-
-        if (top is Toplevel && Top?.Subviews.Count > 1 && Top.Subviews [^1] != top)
-        {
-            Top.BringSubviewToFront (top);
-        }
-    }
-
-    /// <summary>Gets the current visible Toplevel overlapped child that matches the arguments pattern.</summary>
-    /// <param name="type">The type.</param>
-    /// <param name="exclude">The strings to exclude.</param>
-    /// <returns>The matched view.</returns>
-    public static Toplevel? GetTopOverlappedChild (Type? type = null, string []? exclude = null)
-    {
-        if (OverlappedChildren is null || OverlappedTop is null)
-        {
-            return null;
-        }
-
-        foreach (Toplevel top in OverlappedChildren)
-        {
-            if (type is { } && top.GetType () == type && exclude?.Contains (top.Data.ToString ()) == false)
-            {
-                return top;
-            }
-
-            if ((type is { } && top.GetType () != type) || exclude?.Contains (top.Data.ToString ()) == true)
-            {
-                continue;
-            }
-
-            return top;
-        }
-
-        return null;
-    }
-
-    /// <summary>
-    ///     Move to the next Overlapped child from the <see cref="OverlappedTop"/> and set it as the <see cref="Top"/> if
-    ///     it is not already.
-    /// </summary>
-    /// <param name="top"></param>
+    /// <param name="view"></param>
     /// <returns></returns>
-    public static bool MoveToOverlappedChild (Toplevel top)
-    {
-        if (top.Visible && OverlappedTop is { } && Current?.Modal == false)
-        {
-            lock (_topLevels)
-            {
-                _topLevels.MoveTo (top, 0, new ToplevelEqualityComparer ());
-                Current = top;
-            }
-
-            return true;
-        }
-
-        return false;
-    }
-
-    /// <summary>Move to the next Overlapped child from the <see cref="OverlappedTop"/>.</summary>
-    public static void OverlappedMoveNext ()
-    {
-        if (OverlappedTop is { } && !Current!.Modal)
-        {
-            lock (_topLevels)
-            {
-                _topLevels.MoveNext ();
-                var isOverlapped = false;
-
-                while (_topLevels.Peek () == OverlappedTop || !_topLevels.Peek ().Visible)
-                {
-                    if (!isOverlapped && _topLevels.Peek () == OverlappedTop)
-                    {
-                        isOverlapped = true;
-                    }
-                    else if (isOverlapped && _topLevels.Peek () == OverlappedTop)
-                    {
-                        MoveCurrent (Top!);
-
-                        break;
-                    }
-
-                    _topLevels.MoveNext ();
-                }
-
-                Current = _topLevels.Peek ();
-            }
-        }
-    }
-
-    /// <summary>Move to the previous Overlapped child from the <see cref="OverlappedTop"/>.</summary>
-    public static void OverlappedMovePrevious ()
-    {
-        if (OverlappedTop is { } && !Current!.Modal)
-        {
-            lock (_topLevels)
-            {
-                _topLevels.MovePrevious ();
-                var isOverlapped = false;
-
-                while (_topLevels.Peek () == OverlappedTop || !_topLevels.Peek ().Visible)
-                {
-                    if (!isOverlapped && _topLevels.Peek () == OverlappedTop)
-                    {
-                        isOverlapped = true;
-                    }
-                    else if (isOverlapped && _topLevels.Peek () == OverlappedTop)
-                    {
-                        MoveCurrent (Top!);
-
-                        break;
-                    }
-
-                    _topLevels.MovePrevious ();
-                }
-
-                Current = _topLevels.Peek ();
-            }
-        }
-    }
-
-    private static bool OverlappedChildNeedsDisplay ()
-    {
-        if (OverlappedTop is null)
-        {
-            return false;
-        }
-
-        lock (_topLevels)
-        {
-            foreach (Toplevel top in _topLevels)
-            {
-                if (top != Current && top.Visible && (top.NeedsDisplay || top.SubViewNeedsDisplay || top.LayoutNeeded))
-                {
-                    OverlappedTop.SetSubViewNeedsDisplay ();
-
-                    return true;
-                }
-            }
-        }
-
-        return false;
-    }
-
-    private static bool SetCurrentOverlappedAsTop ()
-    {
-        if (OverlappedTop is null && Current != Top && Current?.SuperView is null && Current?.Modal == false)
-        {
-            Top = Current;
-
-            return true;
-        }
-
-        return false;
-    }
-
-    /// <summary>
-    ///     Finds the first Toplevel in the stack that is Visible and who's Frame contains the <paramref name="location"/>.
-    /// </summary>
-    /// <param name="start"></param>
-    /// <param name="location"></param>
-    /// <returns></returns>
-    private static Toplevel? FindDeepestTop (Toplevel start, in Point location)
-    {
-        if (!start.Frame.Contains (location))
-        {
-            return null;
-        }
-
-        lock (_topLevels)
-        {
-            if (_topLevels is not { Count: > 0 })
-            {
-                return start;
-            }
-
-            int rx = location.X - start.Frame.X;
-            int ry = location.Y - start.Frame.Y;
-
-            foreach (Toplevel t in _topLevels)
-            {
-                if (t == Current)
-                {
-                    continue;
-                }
-
-                if (t != start && t.Visible && t.Frame.Contains (rx, ry))
-                {
-                    start = t;
-
-                    break;
-                }
-            }
-        }
-
-        return start;
-    }
-
-    /// <summary>
-    ///     Given <paramref name="view"/>, returns the first Superview up the chain that is <see cref="Top"/>.
-    /// </summary>
-    private static View? FindTopFromView (View? view)
+    internal static View? GetDeepestFocusedSubview (View? view)
     {
         if (view is null)
         {
             return null;
         }
 
-        View top = view.SuperView is { } && view.SuperView != Top
-                       ? view.SuperView
-                       : view;
-
-        while (top?.SuperView is { } && top?.SuperView != Top)
+        foreach (View v in view.Subviews)
         {
-            top = top!.SuperView;
+            if (v.HasFocus)
+            {
+                return GetDeepestFocusedSubview (v);
+            }
         }
 
-        return top;
+        return view;
     }
 
     /// <summary>
-    ///     If the <see cref="Current"/> is not the <paramref name="top"/> then <paramref name="top"/> is moved to the top of
-    ///     the Toplevel stack and made Current.
+    ///    Sets the focus to the next view in the <see cref="View.TabIndexes"/> list. If the last view is focused, the first view is focused.
     /// </summary>
-    /// <param name="top"></param>
-    /// <returns></returns>
-    private static bool MoveCurrent (Toplevel top)
+    /// <param name="viewsInTabIndexes"></param>
+    /// <param name="direction"></param>
+    internal static void FocusNearestView (IEnumerable<View>? viewsInTabIndexes, View.NavigationDirection direction)
     {
-        // The Current is modal and the top is not modal Toplevel then
-        // the Current must be moved above the first not modal Toplevel.
-        if (OverlappedTop is { }
-            && top != OverlappedTop
-            && top != Current
-            && Current?.Modal == true
-            && !_topLevels.Peek ().Modal)
+        if (viewsInTabIndexes is null)
         {
-            lock (_topLevels)
+            return;
+        }
+
+        var found = false;
+        var focusProcessed = false;
+        var idx = 0;
+
+        foreach (View v in viewsInTabIndexes)
+        {
+            if (v == Application.Current)
             {
-                _topLevels.MoveTo (Current, 0, new ToplevelEqualityComparer ());
+                found = true;
             }
 
-            var index = 0;
-            Toplevel [] savedToplevels = _topLevels.ToArray ();
-
-            foreach (Toplevel t in savedToplevels)
+            if (found && v != Application.Current)
             {
-                if (!t!.Modal && t != Current && t != top && t != savedToplevels [index])
+                if (direction == View.NavigationDirection.Forward)
                 {
-                    lock (_topLevels)
-                    {
-                        _topLevels.MoveTo (top, index, new ToplevelEqualityComparer ());
-                    }
+                    Application.Current!.SuperView?.FocusNext ();
+                }
+                else
+                {
+                    Application.Current!.SuperView?.FocusPrev ();
                 }
 
-                index++;
-            }
+                focusProcessed = true;
 
-            return false;
-        }
-
-        // The Current and the top are both not running Toplevel then
-        // the top must be moved above the first not running Toplevel.
-        if (OverlappedTop is { }
-            && top != OverlappedTop
-            && top != Current
-            && Current?.Running == false
-            && top?.Running == false)
-        {
-            lock (_topLevels)
-            {
-                _topLevels.MoveTo (Current, 0, new ToplevelEqualityComparer ());
-            }
-
-            var index = 0;
-
-            foreach (Toplevel t in _topLevels.ToArray ())
-            {
-                if (!t.Running && t != Current && index > 0)
+                if (Application.Current.SuperView?.Focused is { } && Application.Current.SuperView.Focused != Application.Current)
                 {
-                    lock (_topLevels)
-                    {
-                        _topLevels.MoveTo (top, index - 1, new ToplevelEqualityComparer ());
-                    }
+                    return;
                 }
-
-                index++;
             }
-
-            return false;
-        }
-
-        if ((OverlappedTop is { } && top?.Modal == true && _topLevels.Peek () != top)
-            || (OverlappedTop is { } && Current != OverlappedTop && Current?.Modal == false && top == OverlappedTop)
-            || (OverlappedTop is { } && Current?.Modal == false && top != Current)
-            || (OverlappedTop is { } && Current?.Modal == true && top == OverlappedTop))
-        {
-            lock (_topLevels)
+            else if (found && !focusProcessed && idx == viewsInTabIndexes.Count () - 1)
             {
-                _topLevels.MoveTo (top, 0, new ToplevelEqualityComparer ());
-                Current = top;
+                viewsInTabIndexes.ToList () [0].SetFocus ();
             }
+
+            idx++;
+        }
+    }
+    /// <summary>
+    ///     Moves the focus to 
+    /// </summary>
+    internal static void MoveNextView ()
+    {
+        View? old = GetDeepestFocusedSubview (Application.Current!.Focused);
+
+        if (!Application.Current.FocusNext ())
+        {
+            Application.Current.FocusNext ();
         }
 
-        return true;
+        if (old != Application.Current.Focused && old != Application.Current.Focused?.Focused)
+        {
+            old?.SetNeedsDisplay ();
+            Application.Current.Focused?.SetNeedsDisplay ();
+        }
+        else
+        {
+            FocusNearestView (Application.Current.SuperView?.TabIndexes, View.NavigationDirection.Forward);
+        }
+    }
+
+    internal static void MoveNextViewOrTop ()
+    {
+        if (ApplicationOverlapped.OverlappedTop is null)
+        {
+            Toplevel? top = Application.Current!.Modal ? Application.Current : Application.Top;
+            top!.FocusNext ();
+
+            if (top.Focused is null)
+            {
+                top.FocusNext ();
+            }
+
+            top.SetNeedsDisplay ();
+            ApplicationOverlapped.BringOverlappedTopToFront ();
+        }
+        else
+        {
+            ApplicationOverlapped.OverlappedMoveNext ();
+        }
+    }
+
+    internal static void MovePreviousView ()
+    {
+        View? old = GetDeepestFocusedSubview (Application.Current!.Focused);
+
+        if (!Application.Current.FocusPrev ())
+        {
+            Application.Current.FocusPrev ();
+        }
+
+        if (old != Application.Current.Focused && old != Application.Current.Focused?.Focused)
+        {
+            old?.SetNeedsDisplay ();
+            Application.Current.Focused?.SetNeedsDisplay ();
+        }
+        else
+        {
+            FocusNearestView (Application.Current.SuperView?.TabIndexes?.Reverse (), View.NavigationDirection.Backward);
+        }
+    }
+
+    internal static void MovePreviousViewOrTop ()
+    {
+        if (ApplicationOverlapped.OverlappedTop is null)
+        {
+            Toplevel? top = Application.Current!.Modal ? Application.Current : Application.Top;
+            top!.FocusPrev ();
+
+            if (top.Focused is null)
+            {
+                top.FocusPrev ();
+            }
+
+            top.SetNeedsDisplay ();
+            ApplicationOverlapped.BringOverlappedTopToFront ();
+        }
+        else
+        {
+            ApplicationOverlapped.OverlappedMovePrevious ();
+        }
     }
 }
diff --git a/Terminal.Gui/Application/Application.Overlapped.cs b/Terminal.Gui/Application/Application.Overlapped.cs
index 26e931c98..ce88c1567 100644
--- a/Terminal.Gui/Application/Application.Overlapped.cs
+++ b/Terminal.Gui/Application/Application.Overlapped.cs
@@ -1,170 +1,373 @@
 #nullable enable
-using static Terminal.Gui.View;
-using System.Reflection;
-
 namespace Terminal.Gui;
 
-internal static class ViewNavigation
+/// <summary>
+/// Helper class for managing overlapped views in the application.
+/// </summary>
+public static class ApplicationOverlapped
 {
     /// <summary>
-    ///    Gets the deepest focused subview of the specified <paramref name="view"/>.
+    ///     Gets the list of the Overlapped children which are not modal <see cref="Toplevel"/> from the
+    ///     <see cref="OverlappedTop"/>.
     /// </summary>
-    /// <param name="view"></param>
+    public static List<Toplevel>? OverlappedChildren
+    {
+        get
+        {
+            if (OverlappedTop is { })
+            {
+                List<Toplevel> overlappedChildren = new ();
+
+                lock (Application.TopLevels)
+                {
+                    foreach (Toplevel top in Application.TopLevels)
+                    {
+                        if (top != OverlappedTop && !top.Modal)
+                        {
+                            overlappedChildren.Add (top);
+                        }
+                    }
+                }
+
+                return overlappedChildren;
+            }
+
+            return null;
+        }
+    }
+
+    /// <summary>
+    ///     The <see cref="Toplevel"/> object used for the application on startup which
+    ///     <see cref="Toplevel.IsOverlappedContainer"/> is true.
+    /// </summary>
+    public static Toplevel? OverlappedTop
+    {
+        get
+        {
+            if (Application.Top is { IsOverlappedContainer: true })
+            {
+                return Application.Top;
+            }
+
+            return null;
+        }
+    }
+
+    /// <summary>Brings the superview of the most focused overlapped view is on front.</summary>
+    public static void BringOverlappedTopToFront ()
+    {
+        if (OverlappedTop is { })
+        {
+            return;
+        }
+
+        View? top = FindTopFromView (Application.Top?.MostFocused);
+
+        if (top is Toplevel && Application.Top?.Subviews.Count > 1 && Application.Top.Subviews [^1] != top)
+        {
+            Application.Top.BringSubviewToFront (top);
+        }
+    }
+
+    /// <summary>Gets the current visible Toplevel overlapped child that matches the arguments pattern.</summary>
+    /// <param name="type">The type.</param>
+    /// <param name="exclude">The strings to exclude.</param>
+    /// <returns>The matched view.</returns>
+    public static Toplevel? GetTopOverlappedChild (Type? type = null, string []? exclude = null)
+    {
+        if (OverlappedChildren is null || OverlappedTop is null)
+        {
+            return null;
+        }
+
+        foreach (Toplevel top in OverlappedChildren)
+        {
+            if (type is { } && top.GetType () == type && exclude?.Contains (top.Data.ToString ()) == false)
+            {
+                return top;
+            }
+
+            if ((type is { } && top.GetType () != type) || exclude?.Contains (top.Data.ToString ()) == true)
+            {
+                continue;
+            }
+
+            return top;
+        }
+
+        return null;
+    }
+
+    /// <summary>
+    ///     Move to the next Overlapped child from the <see cref="OverlappedTop"/> and set it as the <see cref="Top"/> if
+    ///     it is not already.
+    /// </summary>
+    /// <param name="top"></param>
     /// <returns></returns>
-    internal static View? GetDeepestFocusedSubview (View? view)
+    public static bool MoveToOverlappedChild (Toplevel? top)
+    {
+        if (top is null)
+        {
+            return false;
+        }
+        if (top.Visible && OverlappedTop is { } && Application.Current?.Modal == false)
+        {
+            lock (Application.TopLevels)
+            {
+                Application.TopLevels.MoveTo (top, 0, new ToplevelEqualityComparer ());
+                Application.Current = top;
+            }
+
+            return true;
+        }
+
+        return false;
+    }
+
+    /// <summary>Move to the next Overlapped child from the <see cref="OverlappedTop"/>.</summary>
+    public static void OverlappedMoveNext ()
+    {
+        if (OverlappedTop is { } && !Application.Current!.Modal)
+        {
+            lock (Application.TopLevels)
+            {
+                Application.TopLevels.MoveNext ();
+                var isOverlapped = false;
+
+                while (Application.TopLevels.Peek () == OverlappedTop || !Application.TopLevels.Peek ().Visible)
+                {
+                    if (!isOverlapped && Application.TopLevels.Peek () == OverlappedTop)
+                    {
+                        isOverlapped = true;
+                    }
+                    else if (isOverlapped && Application.TopLevels.Peek () == OverlappedTop)
+                    {
+                        MoveCurrent (Application.Top!);
+
+                        break;
+                    }
+
+                    Application.TopLevels.MoveNext ();
+                }
+
+                Application.Current = Application.TopLevels.Peek ();
+            }
+        }
+    }
+
+    /// <summary>Move to the previous Overlapped child from the <see cref="OverlappedTop"/>.</summary>
+    public static void OverlappedMovePrevious ()
+    {
+        if (OverlappedTop is { } && !Application.Current!.Modal)
+        {
+            lock (Application.TopLevels)
+            {
+                Application.TopLevels.MovePrevious ();
+                var isOverlapped = false;
+
+                while (Application.TopLevels.Peek () == OverlappedTop || !Application.TopLevels.Peek ().Visible)
+                {
+                    if (!isOverlapped && Application.TopLevels.Peek () == OverlappedTop)
+                    {
+                        isOverlapped = true;
+                    }
+                    else if (isOverlapped && Application.TopLevels.Peek () == OverlappedTop)
+                    {
+                        MoveCurrent (Application.Top!);
+
+                        break;
+                    }
+
+                    Application.TopLevels.MovePrevious ();
+                }
+
+                 Application.Current = Application.TopLevels.Peek ();
+            }
+        }
+    }
+
+    internal static bool OverlappedChildNeedsDisplay ()
+    {
+        if (OverlappedTop is null)
+        {
+            return false;
+        }
+
+        lock (Application.TopLevels)
+        {
+            foreach (Toplevel top in Application.TopLevels)
+            {
+                if (top != Application.Current && top.Visible && (top.NeedsDisplay || top.SubViewNeedsDisplay || top.LayoutNeeded))
+                {
+                    OverlappedTop.SetSubViewNeedsDisplay ();
+
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+
+    internal static bool SetCurrentOverlappedAsTop ()
+    {
+        if (OverlappedTop is null && Application.Current != Application.Top && Application.Current?.SuperView is null && Application.Current?.Modal == false)
+        {
+            Application.Top = Application.Current;
+
+            return true;
+        }
+
+        return false;
+    }
+
+    /// <summary>
+    ///     Finds the first Toplevel in the stack that is Visible and who's Frame contains the <paramref name="location"/>.
+    /// </summary>
+    /// <param name="start"></param>
+    /// <param name="location"></param>
+    /// <returns></returns>
+    internal static Toplevel? FindDeepestTop (Toplevel start, in Point location)
+    {
+        if (!start.Frame.Contains (location))
+        {
+            return null;
+        }
+
+        lock (Application.TopLevels)
+        {
+            if (Application.TopLevels is not { Count: > 0 })
+            {
+                return start;
+            }
+
+            int rx = location.X - start.Frame.X;
+            int ry = location.Y - start.Frame.Y;
+
+            foreach (Toplevel t in Application.TopLevels)
+            {
+                if (t == Application.Current)
+                {
+                    continue;
+                }
+
+                if (t != start && t.Visible && t.Frame.Contains (rx, ry))
+                {
+                    start = t;
+
+                    break;
+                }
+            }
+        }
+
+        return start;
+    }
+
+    /// <summary>
+    ///     Given <paramref name="view"/>, returns the first Superview up the chain that is <see cref="Top"/>.
+    /// </summary>
+    internal static View? FindTopFromView (View? view)
     {
         if (view is null)
         {
             return null;
         }
 
-        foreach (View v in view.Subviews)
+        View top = view.SuperView is { } && view.SuperView != Application.Top
+                       ? view.SuperView
+                       : view;
+
+        while (top?.SuperView is { } && top?.SuperView != Application.Top)
         {
-            if (v.HasFocus)
-            {
-                return GetDeepestFocusedSubview (v);
-            }
+            top = top!.SuperView;
         }
 
-        return view;
+        return top;
     }
 
     /// <summary>
-    ///    Sets the focus to the next view in the <see cref="View.TabIndexes"/> list. If the last view is focused, the first view is focused.
+    ///     If the <see cref="Current"/> is not the <paramref name="top"/> then <paramref name="top"/> is moved to the top of
+    ///     the Toplevel stack and made Current.
     /// </summary>
-    /// <param name="viewsInTabIndexes"></param>
-    /// <param name="direction"></param>
-    internal static void FocusNearestView (IEnumerable<View>? viewsInTabIndexes, NavigationDirection direction)
+    /// <param name="top"></param>
+    /// <returns></returns>
+    internal static bool MoveCurrent (Toplevel top)
     {
-        if (viewsInTabIndexes is null)
+        // The Current is modal and the top is not modal Toplevel then
+        // the Current must be moved above the first not modal Toplevel.
+        if (OverlappedTop is { }
+            && top != OverlappedTop
+            && top != Application.Current
+            && Application.Current?.Modal == true
+            && !Application.TopLevels.Peek ().Modal)
         {
-            return;
-        }
-
-        var found = false;
-        var focusProcessed = false;
-        var idx = 0;
-
-        foreach (View v in viewsInTabIndexes)
-        {
-            if (v == Application.Current)
+            lock (Application.TopLevels)
             {
-                found = true;
+                Application.TopLevels.MoveTo (Application.Current, 0, new ToplevelEqualityComparer ());
             }
 
-            if (found && v != Application.Current)
+            var index = 0;
+            Toplevel [] savedToplevels = Application.TopLevels.ToArray ();
+
+            foreach (Toplevel t in savedToplevels)
             {
-                if (direction == NavigationDirection.Forward)
+                if (!t!.Modal && t != Application.Current && t != top && t != savedToplevels [index])
                 {
-                    Application.Current!.SuperView?.FocusNext ();
-                }
-                else
-                {
-                    Application.Current!.SuperView?.FocusPrev ();
+                    lock (Application.TopLevels)
+                    {
+                        Application.TopLevels.MoveTo (top, index, new ToplevelEqualityComparer ());
+                    }
                 }
 
-                focusProcessed = true;
+                index++;
+            }
 
-                if (Application.Current.SuperView?.Focused is { } && Application.Current.SuperView.Focused != Application.Current)
+            return false;
+        }
+
+        // The Current and the top are both not running Toplevel then
+        // the top must be moved above the first not running Toplevel.
+        if (OverlappedTop is { }
+            && top != OverlappedTop
+            && top != Application.Current
+            && Application.Current?.Running == false
+            && top?.Running == false)
+        {
+            lock (Application.TopLevels)
+            {
+                Application.TopLevels.MoveTo (Application.Current, 0, new ToplevelEqualityComparer ());
+            }
+
+            var index = 0;
+
+            foreach (Toplevel t in Application.TopLevels.ToArray ())
+            {
+                if (!t.Running && t != Application.Current && index > 0)
                 {
-                    return;
+                    lock (Application.TopLevels)
+                    {
+                        Application.TopLevels.MoveTo (top, index - 1, new ToplevelEqualityComparer ());
+                    }
                 }
+
+                index++;
             }
-            else if (found && !focusProcessed && idx == viewsInTabIndexes.Count () - 1)
+
+            return false;
+        }
+
+        if ((OverlappedTop is { } && top?.Modal == true && Application.TopLevels.Peek () != top)
+            || (OverlappedTop is { } && Application.Current != OverlappedTop && Application.Current?.Modal == false && top == OverlappedTop)
+            || (OverlappedTop is { } && Application.Current?.Modal == false && top != Application.Current)
+            || (OverlappedTop is { } && Application.Current?.Modal == true && top == OverlappedTop))
+        {
+            lock (Application.TopLevels)
             {
-                viewsInTabIndexes.ToList () [0].SetFocus ();
+                Application.TopLevels.MoveTo (top, 0, new ToplevelEqualityComparer ());
+                Application.Current = top;
             }
-
-            idx++;
-        }
-    }
-    /// <summary>
-    ///     Moves the focus to 
-    /// </summary>
-    internal static void MoveNextView ()
-    {
-        View? old = GetDeepestFocusedSubview (Application.Current!.Focused);
-
-        if (!Application.Current.FocusNext ())
-        {
-            Application.Current.FocusNext ();
         }
 
-        if (old != Application.Current.Focused && old != Application.Current.Focused?.Focused)
-        {
-            old?.SetNeedsDisplay ();
-            Application.Current.Focused?.SetNeedsDisplay ();
-        }
-        else
-        {
-            FocusNearestView (Application.Current.SuperView?.TabIndexes, NavigationDirection.Forward);
-        }
-    }
-
-    internal static void MoveNextViewOrTop ()
-    {
-        if (Application.OverlappedTop is null)
-        {
-            Toplevel? top = Application.Current!.Modal ? Application.Current : Application.Top;
-            top!.FocusNext ();
-
-            if (top.Focused is null)
-            {
-                top.FocusNext ();
-            }
-
-            top.SetNeedsDisplay ();
-            Application.BringOverlappedTopToFront ();
-        }
-        else
-        {
-            Application.OverlappedMoveNext ();
-        }
-    }
-
-    internal static void MovePreviousView ()
-    {
-        View? old = GetDeepestFocusedSubview (Application.Current!.Focused);
-
-        if (!Application.Current.FocusPrev ())
-        {
-            Application.Current.FocusPrev ();
-        }
-
-        if (old != Application.Current.Focused && old != Application.Current.Focused?.Focused)
-        {
-            old?.SetNeedsDisplay ();
-            Application.Current.Focused?.SetNeedsDisplay ();
-        }
-        else
-        {
-            FocusNearestView (Application.Current.SuperView?.TabIndexes?.Reverse (), NavigationDirection.Backward);
-        }
-    }
-
-    internal static void MovePreviousViewOrTop ()
-    {
-        if (Application.OverlappedTop is null)
-        {
-            Toplevel? top = Application.Current!.Modal ? Application.Current : Application.Top;
-            top!.FocusPrev ();
-
-            if (top.Focused is null)
-            {
-                top.FocusPrev ();
-            }
-
-            top.SetNeedsDisplay ();
-            Application.BringOverlappedTopToFront ();
-        }
-        else
-        {
-            Application.OverlappedMovePrevious ();
-        }
+        return true;
     }
 }
-
-public static partial class Application // App-level View Navigation
-{
- 
-}
\ No newline at end of file
diff --git a/Terminal.Gui/Application/Application.Run.cs b/Terminal.Gui/Application/Application.Run.cs
index 87bfde4c0..3e088c348 100644
--- a/Terminal.Gui/Application/Application.Run.cs
+++ b/Terminal.Gui/Application/Application.Run.cs
@@ -54,7 +54,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
         }
 #endif
 
-        if (toplevel.IsOverlappedContainer && OverlappedTop != toplevel && OverlappedTop is { })
+        if (toplevel.IsOverlappedContainer && ApplicationOverlapped.OverlappedTop != toplevel && ApplicationOverlapped.OverlappedTop is { })
         {
             throw new InvalidOperationException ("Only one Overlapped Container is allowed.");
         }
@@ -72,7 +72,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
         }
 
 #if DEBUG_IDISPOSABLE
-        if (Top is { } && toplevel != Top && !_topLevels.Contains (Top))
+        if (Top is { } && toplevel != Top && !TopLevels.Contains (Top))
         {
             // This assertion confirm if the Top was already disposed
             Debug.Assert (Top.WasDisposed);
@@ -80,9 +80,9 @@ public static partial class Application // Run (Begin, Run, End, Stop)
         }
 #endif
 
-        lock (_topLevels)
+        lock (TopLevels)
         {
-            if (Top is { } && toplevel != Top && !_topLevels.Contains (Top))
+            if (Top is { } && toplevel != Top && !TopLevels.Contains (Top))
             {
                 // If Top was already disposed and isn't on the Toplevels Stack,
                 // clean it up here if is the same as _cachedRunStateToplevel
@@ -96,7 +96,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
                     throw new ObjectDisposedException (Top.GetType ().FullName);
                 }
             }
-            else if (OverlappedTop is { } && toplevel != Top && _topLevels.Contains (Top!))
+            else if (ApplicationOverlapped.OverlappedTop is { } && toplevel != Top && TopLevels.Contains (Top!))
             {
                 Top!.OnLeave (toplevel);
             }
@@ -106,29 +106,29 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             if (string.IsNullOrEmpty (toplevel.Id))
             {
                 var count = 1;
-                var id = (_topLevels.Count + count).ToString ();
+                var id = (TopLevels.Count + count).ToString ();
 
-                while (_topLevels.Count > 0 && _topLevels.FirstOrDefault (x => x.Id == id) is { })
+                while (TopLevels.Count > 0 && TopLevels.FirstOrDefault (x => x.Id == id) is { })
                 {
                     count++;
-                    id = (_topLevels.Count + count).ToString ();
+                    id = (TopLevels.Count + count).ToString ();
                 }
 
-                toplevel.Id = (_topLevels.Count + count).ToString ();
+                toplevel.Id = (TopLevels.Count + count).ToString ();
 
-                _topLevels.Push (toplevel);
+                TopLevels.Push (toplevel);
             }
             else
             {
-                Toplevel? dup = _topLevels.FirstOrDefault (x => x.Id == toplevel.Id);
+                Toplevel? dup = TopLevels.FirstOrDefault (x => x.Id == toplevel.Id);
 
                 if (dup is null)
                 {
-                    _topLevels.Push (toplevel);
+                    TopLevels.Push (toplevel);
                 }
             }
 
-            if (_topLevels.FindDuplicates (new ToplevelEqualityComparer ()).Count > 0)
+            if (TopLevels.FindDuplicates (new ToplevelEqualityComparer ()).Count > 0)
             {
                 throw new ArgumentException ("There are duplicates Toplevel IDs");
             }
@@ -141,7 +141,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
 
         var refreshDriver = true;
 
-        if (OverlappedTop is null
+        if (ApplicationOverlapped.OverlappedTop is null
             || toplevel.IsOverlappedContainer
             || (Current?.Modal == false && toplevel.Modal)
             || (Current?.Modal == false && !toplevel.Modal)
@@ -154,25 +154,25 @@ public static partial class Application // Run (Begin, Run, End, Stop)
                 Current = toplevel;
                 Current.OnActivate (previousCurrent);
 
-                SetCurrentOverlappedAsTop ();
+                ApplicationOverlapped.SetCurrentOverlappedAsTop ();
             }
             else
             {
                 refreshDriver = false;
             }
         }
-        else if ((toplevel != OverlappedTop
+        else if ((toplevel != ApplicationOverlapped.OverlappedTop
                   && Current?.Modal == true
-                  && !_topLevels.Peek ().Modal)
-                 || (toplevel != OverlappedTop && Current?.Running == false))
+                  && !TopLevels.Peek ().Modal)
+                 || (toplevel != ApplicationOverlapped.OverlappedTop && Current?.Running == false))
         {
             refreshDriver = false;
-            MoveCurrent (toplevel);
+            ApplicationOverlapped.MoveCurrent (toplevel);
         }
         else
         {
             refreshDriver = false;
-            MoveCurrent (Current!);
+            ApplicationOverlapped.MoveCurrent (Current!);
         }
 
         toplevel.SetRelativeLayout (Driver!.Screen.Size);
@@ -180,11 +180,11 @@ public static partial class Application // Run (Begin, Run, End, Stop)
         toplevel.LayoutSubviews ();
         toplevel.PositionToplevels ();
         toplevel.FocusFirst ();
-        BringOverlappedTopToFront ();
+        ApplicationOverlapped.BringOverlappedTopToFront ();
 
         if (refreshDriver)
         {
-            OverlappedTop?.OnChildLoaded (toplevel);
+            ApplicationOverlapped.OverlappedTop?.OnChildLoaded (toplevel);
             toplevel.OnLoaded ();
             toplevel.SetNeedsDisplay ();
             toplevel.Draw ();
@@ -427,7 +427,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             if (runState.Toplevel is null)
             {
 #if DEBUG_IDISPOSABLE
-                Debug.Assert (_topLevels.Count == 0);
+                Debug.Assert (TopLevels.Count == 0);
 #endif
                 runState.Dispose ();
 
@@ -499,7 +499,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
         // TODO: Figure out how to remove this call to ClearContents. Refresh should just repaint damaged areas, not clear
         Driver!.ClearContents ();
 
-        foreach (Toplevel v in _topLevels.Reverse ())
+        foreach (Toplevel v in TopLevels.Reverse ())
         {
             if (v.Visible)
             {
@@ -577,9 +577,9 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             // TODO: Overlapped - Move elsewhere
             if (state.Toplevel != Current)
             {
-                OverlappedTop?.OnDeactivate (state.Toplevel);
+                ApplicationOverlapped.OverlappedTop?.OnDeactivate (state.Toplevel);
                 state.Toplevel = Current;
-                OverlappedTop?.OnActivate (state.Toplevel);
+                ApplicationOverlapped.OverlappedTop?.OnActivate (state.Toplevel);
                 Top!.SetSubViewNeedsDisplay ();
                 Refresh ();
             }
@@ -597,7 +597,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             state.Toplevel!.SetNeedsDisplay (state.Toplevel.Frame);
             Top.Draw ();
 
-            foreach (Toplevel top in _topLevels.Reverse ())
+            foreach (Toplevel top in TopLevels.Reverse ())
             {
                 if (top != Top && top != state.Toplevel)
                 {
@@ -608,7 +608,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             }
         }
 
-        if (_topLevels.Count == 1
+        if (TopLevels.Count == 1
             && state.Toplevel == Top
             && (Driver!.Cols != state.Toplevel!.Frame.Width
                 || Driver!.Rows != state.Toplevel.Frame.Height)
@@ -619,7 +619,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             Driver.ClearContents ();
         }
 
-        if (state.Toplevel!.NeedsDisplay || state.Toplevel.SubViewNeedsDisplay || state.Toplevel.LayoutNeeded || OverlappedChildNeedsDisplay ())
+        if (state.Toplevel!.NeedsDisplay || state.Toplevel.SubViewNeedsDisplay || state.Toplevel.LayoutNeeded || ApplicationOverlapped.OverlappedChildNeedsDisplay ())
         {
             state.Toplevel.SetNeedsDisplay ();
             state.Toplevel.Draw ();
@@ -659,19 +659,19 @@ public static partial class Application // Run (Begin, Run, End, Stop)
     /// </remarks>
     public static void RequestStop (Toplevel? top = null)
     {
-        if (OverlappedTop is null || top is null)
+        if (ApplicationOverlapped.OverlappedTop is null || top is null)
         {
             top = Current;
         }
 
-        if (OverlappedTop != null
+        if (ApplicationOverlapped.OverlappedTop != null
             && top!.IsOverlappedContainer
             && top?.Running == true
             && (Current?.Modal == false || Current is { Modal: true, Running: false }))
         {
-            OverlappedTop.RequestStop ();
+            ApplicationOverlapped.OverlappedTop.RequestStop ();
         }
-        else if (OverlappedTop != null
+        else if (ApplicationOverlapped.OverlappedTop != null
                  && top != Current
                  && Current is { Running: true, Modal: true }
                  && top!.Modal
@@ -698,21 +698,21 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             top.Running = false;
             OnNotifyStopRunState (top);
         }
-        else if ((OverlappedTop != null
-                  && top != OverlappedTop
+        else if ((ApplicationOverlapped.OverlappedTop != null
+                  && top != ApplicationOverlapped.OverlappedTop
                   && top != Current
                   && Current is { Modal: false, Running: true }
                   && !top!.Running)
-                 || (OverlappedTop != null
-                     && top != OverlappedTop
+                 || (ApplicationOverlapped.OverlappedTop != null
+                     && top != ApplicationOverlapped.OverlappedTop
                      && top != Current
                      && Current is { Modal: false, Running: false }
                      && !top!.Running
-                     && _topLevels.ToArray () [1].Running))
+                     && TopLevels.ToArray () [1].Running))
         {
-            MoveCurrent (top);
+            ApplicationOverlapped.MoveCurrent (top);
         }
-        else if (OverlappedTop != null
+        else if (ApplicationOverlapped.OverlappedTop != null
                  && Current != top
                  && Current?.Running == true
                  && !top!.Running
@@ -723,9 +723,9 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             Current.Running = false;
             OnNotifyStopRunState (Current);
         }
-        else if (OverlappedTop != null
+        else if (ApplicationOverlapped.OverlappedTop != null
                  && Current == top
-                 && OverlappedTop?.Running == true
+                 && ApplicationOverlapped.OverlappedTop?.Running == true
                  && Current?.Running == true
                  && top!.Running
                  && Current?.Modal == true
@@ -784,9 +784,9 @@ public static partial class Application // Run (Begin, Run, End, Stop)
     {
         ArgumentNullException.ThrowIfNull (runState);
 
-        if (OverlappedTop is { })
+        if (ApplicationOverlapped.OverlappedTop is { })
         {
-            OverlappedTop.OnChildUnloaded (runState.Toplevel);
+            ApplicationOverlapped.OverlappedTop.OnChildUnloaded (runState.Toplevel);
         }
         else
         {
@@ -795,16 +795,16 @@ public static partial class Application // Run (Begin, Run, End, Stop)
 
         // End the RunState.Toplevel
         // First, take it off the Toplevel Stack
-        if (_topLevels.Count > 0)
+        if (TopLevels.Count > 0)
         {
-            if (_topLevels.Peek () != runState.Toplevel)
+            if (TopLevels.Peek () != runState.Toplevel)
             {
                 // If the top of the stack is not the RunState.Toplevel then
                 // this call to End is not balanced with the call to Begin that started the RunState
                 throw new ArgumentException ("End must be balanced with calls to Begin");
             }
 
-            _topLevels.Pop ();
+            TopLevels.Pop ();
         }
 
         // Notify that it is closing
@@ -812,32 +812,32 @@ public static partial class Application // Run (Begin, Run, End, Stop)
 
         // If there is a OverlappedTop that is not the RunState.Toplevel then RunState.Toplevel
         // is a child of MidTop, and we should notify the OverlappedTop that it is closing
-        if (OverlappedTop is { } && !runState.Toplevel!.Modal && runState.Toplevel != OverlappedTop)
+        if (ApplicationOverlapped.OverlappedTop is { } && !runState.Toplevel!.Modal && runState.Toplevel != ApplicationOverlapped.OverlappedTop)
         {
-            OverlappedTop.OnChildClosed (runState.Toplevel);
+            ApplicationOverlapped.OverlappedTop.OnChildClosed (runState.Toplevel);
         }
 
         // Set Current and Top to the next TopLevel on the stack
-        if (_topLevels.Count == 0)
+        if (TopLevels.Count == 0)
         {
             Current = null;
         }
         else
         {
-            if (_topLevels.Count > 1 && _topLevels.Peek () == OverlappedTop && OverlappedChildren?.Any (t => t.Visible) != null)
+            if (TopLevels.Count > 1 && TopLevels.Peek () == ApplicationOverlapped.OverlappedTop && ApplicationOverlapped.OverlappedChildren?.Any (t => t.Visible) != null)
             {
-                OverlappedMoveNext ();
+                ApplicationOverlapped.OverlappedMoveNext ();
             }
 
-            Current = _topLevels.Peek ();
+            Current = TopLevels.Peek ();
 
-            if (_topLevels.Count == 1 && Current == OverlappedTop)
+            if (TopLevels.Count == 1 && Current == ApplicationOverlapped.OverlappedTop)
             {
-                OverlappedTop.OnAllChildClosed ();
+                ApplicationOverlapped.OverlappedTop.OnAllChildClosed ();
             }
             else
             {
-                SetCurrentOverlappedAsTop ();
+                ApplicationOverlapped.SetCurrentOverlappedAsTop ();
                 runState.Toplevel!.OnLeave (Current);
                 Current.OnEnter (runState.Toplevel);
             }
@@ -848,9 +848,9 @@ public static partial class Application // Run (Begin, Run, End, Stop)
         // Don't dispose runState.Toplevel. It's up to caller dispose it
         // If it's not the same as the current in the RunIteration,
         // it will be fixed later in the next RunIteration.
-        if (OverlappedTop is { } && !_topLevels.Contains (OverlappedTop))
+        if (ApplicationOverlapped.OverlappedTop is { } && !TopLevels.Contains (ApplicationOverlapped.OverlappedTop))
         {
-            _cachedRunStateToplevel = OverlappedTop;
+            _cachedRunStateToplevel = ApplicationOverlapped.OverlappedTop;
         }
         else
         {
diff --git a/Terminal.Gui/Application/Application.Toplevel.cs b/Terminal.Gui/Application/Application.Toplevel.cs
index a050e28f1..a1844b2d0 100644
--- a/Terminal.Gui/Application/Application.Toplevel.cs
+++ b/Terminal.Gui/Application/Application.Toplevel.cs
@@ -4,13 +4,13 @@ namespace Terminal.Gui;
 public static partial class Application // Toplevel handling
 {
     // BUGBUG: Technically, this is not the full lst of TopLevels. There be dragons here, e.g. see how Toplevel.Id is used. What
+
     /// <summary>Holds the stack of TopLevel views.</summary>
-    // about TopLevels that are just a SubView of another View?
-    internal static readonly Stack<Toplevel> _topLevels = new ();
+    internal static Stack<Toplevel> TopLevels { get; } = new ();
 
     /// <summary>The <see cref="Toplevel"/> object used for the application on startup (<seealso cref="Top"/>)</summary>
     /// <value>The top.</value>
-    public static Toplevel? Top { get; private set; }
+    public static Toplevel? Top { get; internal set; }
 
     // TODO: Determine why this can't just return _topLevels.Peek()?
     /// <summary>
@@ -22,7 +22,7 @@ public static partial class Application // Toplevel handling
     ///     This will only be distinct from <see cref="Application.Top"/> in scenarios where <see cref="Toplevel.IsOverlappedContainer"/> is <see langword="true"/>.
     /// </remarks>
     /// <value>The current.</value>
-    public static Toplevel? Current { get; private set; }
+    public static Toplevel? Current { get; internal set; }
 
     /// <summary>
     ///     If <paramref name="topLevel"/> is not already Current and visible, finds the last Modal Toplevel in the stack and makes it Current.
@@ -31,17 +31,17 @@ public static partial class Application // Toplevel handling
     {
         if (!topLevel.Running
             || (topLevel == Current && topLevel.Visible)
-            || OverlappedTop == null
-            || _topLevels.Peek ().Modal)
+            || ApplicationOverlapped.OverlappedTop == null
+            || TopLevels.Peek ().Modal)
         {
             return;
         }
 
-        foreach (Toplevel top in _topLevels.Reverse ())
+        foreach (Toplevel top in TopLevels.Reverse ())
         {
             if (top.Modal && top != Current)
             {
-                MoveCurrent (top);
+                ApplicationOverlapped.MoveCurrent (top);
 
                 return;
             }
@@ -49,47 +49,8 @@ public static partial class Application // Toplevel handling
 
         if (!topLevel.Visible && topLevel == Current)
         {
-            OverlappedMoveNext ();
+            ApplicationOverlapped.OverlappedMoveNext ();
         }
     }
 
-    /// <summary>Invoked when the terminal's size changed. The new size of the terminal is provided.</summary>
-    /// <remarks>
-    ///     Event handlers can set <see cref="SizeChangedEventArgs.Cancel"/> to <see langword="true"/> to prevent
-    ///     <see cref="Application"/> from changing it's size to match the new terminal size.
-    /// </remarks>
-    public static event EventHandler<SizeChangedEventArgs>? SizeChanging;
-
-    /// <summary>
-    ///     Called when the application's size changes. Sets the size of all <see cref="Toplevel"/>s and fires the
-    ///     <see cref="SizeChanging"/> event.
-    /// </summary>
-    /// <param name="args">The new size.</param>
-    /// <returns><see lanword="true"/>if the size was changed.</returns>
-    public static bool OnSizeChanging (SizeChangedEventArgs args)
-    {
-        SizeChanging?.Invoke (null, args);
-
-        if (args.Cancel || args.Size is null)
-        {
-            return false;
-        }
-
-        foreach (Toplevel t in _topLevels)
-        {
-            t.SetRelativeLayout (args.Size.Value);
-            t.LayoutSubviews ();
-            t.PositionToplevels ();
-            t.OnSizeChanging (new (args.Size));
-
-            if (PositionCursor (t))
-            {
-                Driver?.UpdateCursor ();
-            }
-        }
-
-        Refresh ();
-
-        return true;
-    }
 }
diff --git a/Terminal.Gui/Application/Application.cs b/Terminal.Gui/Application/Application.cs
index 75fbd7191..b4b4d1310 100644
--- a/Terminal.Gui/Application/Application.cs
+++ b/Terminal.Gui/Application/Application.cs
@@ -56,12 +56,12 @@ public static partial class Application
         // Shutdown is the bookend for Init. As such it needs to clean up all resources
         // Init created. Apps that do any threading will need to code defensively for this.
         // e.g. see Issue #537
-        foreach (Toplevel? t in _topLevels)
+        foreach (Toplevel? t in TopLevels)
         {
             t!.Running = false;
         }
 
-        _topLevels.Clear ();
+        TopLevels.Clear ();
         Current = null;
 #if DEBUG_IDISPOSABLE
 
diff --git a/Terminal.Gui/View/Adornment/Border.cs b/Terminal.Gui/View/Adornment/Border.cs
index ef841e5b1..41fd02f9d 100644
--- a/Terminal.Gui/View/Adornment/Border.cs
+++ b/Terminal.Gui/View/Adornment/Border.cs
@@ -293,7 +293,7 @@ public class Border : Adornment
         if (!_dragPosition.HasValue && mouseEvent.Flags.HasFlag (MouseFlags.Button1Pressed))
         {
             Parent.SetFocus ();
-            Application.BringOverlappedTopToFront ();
+            ApplicationOverlapped.BringOverlappedTopToFront ();
 
             // Only start grabbing if the user clicks in the Thickness area
             // Adornment.Contains takes Parent SuperView=relative coords.
diff --git a/Terminal.Gui/View/ViewSubViews.cs b/Terminal.Gui/View/ViewSubViews.cs
index 38863828a..5da8dd76a 100644
--- a/Terminal.Gui/View/ViewSubViews.cs
+++ b/Terminal.Gui/View/ViewSubViews.cs
@@ -456,7 +456,7 @@ public partial class View
                         Application.Current.FocusNext ();
                     }
 
-                    Application.BringOverlappedTopToFront ();
+                    ApplicationOverlapped.BringOverlappedTopToFront ();
                 }
             }
 
@@ -489,7 +489,7 @@ public partial class View
 
                 if (this is Toplevel && Application.Current.Focused != this)
                 {
-                    Application.BringOverlappedTopToFront ();
+                    ApplicationOverlapped.BringOverlappedTopToFront ();
                 }
             }
 
diff --git a/Terminal.Gui/Views/TileView.cs b/Terminal.Gui/Views/TileView.cs
index 54ec8a4d2..6eb5fa3bf 100644
--- a/Terminal.Gui/Views/TileView.cs
+++ b/Terminal.Gui/Views/TileView.cs
@@ -908,7 +908,7 @@ public class TileView : View
             {
                 // Start a Drag
                 SetFocus ();
-                Application.BringOverlappedTopToFront ();
+                ApplicationOverlapped.BringOverlappedTopToFront ();
 
                 if (mouseEvent.Flags == MouseFlags.Button1Pressed)
                 {
diff --git a/Terminal.Gui/Views/Toplevel.cs b/Terminal.Gui/Views/Toplevel.cs
index 11d216210..d13ae0766 100644
--- a/Terminal.Gui/Views/Toplevel.cs
+++ b/Terminal.Gui/Views/Toplevel.cs
@@ -239,7 +239,7 @@ public partial class Toplevel : View
                 || Application.Current?.Modal == false
                 || (Application.Current?.Modal == true && Application.Current?.Running == false)))
         {
-            foreach (Toplevel child in Application.OverlappedChildren)
+            foreach (Toplevel child in ApplicationOverlapped.OverlappedChildren!)
             {
                 var ev = new ToplevelClosingEventArgs (this);
 
@@ -369,10 +369,10 @@ public partial class Toplevel : View
             //LayoutSubviews ();
             PositionToplevels ();
 
-            if (this == Application.OverlappedTop)
+            if (this == ApplicationOverlapped.OverlappedTop)
             {
                 // This enables correct draw behavior when switching between overlapped subviews
-                foreach (Toplevel top in Application.OverlappedChildren.AsEnumerable ().Reverse ())
+                foreach (Toplevel top in ApplicationOverlapped.OverlappedChildren!.AsEnumerable ().Reverse ())
                 {
                     if (top.Frame.IntersectsWith (Viewport))
                     {
@@ -437,7 +437,7 @@ public partial class Toplevel : View
         if (Focused is null)
         {
             // TODO: this is an Overlapped hack
-            foreach (Toplevel top in Application.OverlappedChildren)
+            foreach (Toplevel top in ApplicationOverlapped.OverlappedChildren!)
             {
                 if (top != this && top.Visible)
                 {
@@ -607,7 +607,7 @@ public class ToplevelEqualityComparer : IEqualityComparer<Toplevel>
 
 /// <summary>
 ///     Implements the <see cref="IComparer{T}"/> to sort the <see cref="Toplevel"/> from the
-///     <see cref="Application.OverlappedChildren"/> if needed.
+///     <see cref="ApplicationOverlapped.OverlappedChildren"/> if needed.
 /// </summary>
 public sealed class ToplevelComparer : IComparer<Toplevel>
 {
diff --git a/Terminal.Gui/Views/ToplevelOverlapped.cs b/Terminal.Gui/Views/ToplevelOverlapped.cs
index 3541ea091..06dac3694 100644
--- a/Terminal.Gui/Views/ToplevelOverlapped.cs
+++ b/Terminal.Gui/Views/ToplevelOverlapped.cs
@@ -3,7 +3,7 @@
 public partial class Toplevel
 {
     /// <summary>Gets or sets if this Toplevel is in overlapped mode within a Toplevel container.</summary>
-    public bool IsOverlapped => Application.OverlappedTop is { } && Application.OverlappedTop != this && !Modal;
+    public bool IsOverlapped => ApplicationOverlapped.OverlappedTop is { } && ApplicationOverlapped.OverlappedTop != this && !Modal;
 
     /// <summary>Gets or sets if this Toplevel is a container for overlapped children.</summary>
     public bool IsOverlappedContainer { get; set; }
diff --git a/UICatalog/Scenarios/BackgroundWorkerCollection.cs b/UICatalog/Scenarios/BackgroundWorkerCollection.cs
index b2f6cdfa9..d1ce6b825 100644
--- a/UICatalog/Scenarios/BackgroundWorkerCollection.cs
+++ b/UICatalog/Scenarios/BackgroundWorkerCollection.cs
@@ -20,10 +20,10 @@ public class BackgroundWorkerCollection : Scenario
         Application.Run<OverlappedMain> ().Dispose ();
 
 #if DEBUG_IDISPOSABLE
-        if (Application.OverlappedChildren is { })
+        if (ApplicationOverlapped.OverlappedChildren is { })
         {
-            Debug.Assert (Application.OverlappedChildren?.Count == 0);
-            Debug.Assert (Application.Top == Application.OverlappedTop);
+            Debug.Assert (ApplicationOverlapped.OverlappedChildren?.Count == 0);
+            Debug.Assert (Application.Top == ApplicationOverlapped.OverlappedTop);
         }
 #endif
 
@@ -134,7 +134,7 @@ public class BackgroundWorkerCollection : Scenario
         {
             var index = 1;
             List<MenuItem> menuItems = new ();
-            List<Toplevel> sortedChildren = Application.OverlappedChildren;
+            List<Toplevel> sortedChildren = ApplicationOverlapped.OverlappedChildren;
             sortedChildren.Sort (new ToplevelComparer ());
 
             foreach (Toplevel top in sortedChildren)
@@ -151,7 +151,7 @@ public class BackgroundWorkerCollection : Scenario
                 string topTitle = top is Window ? ((Window)top).Title : top.Data.ToString ();
                 string itemTitle = item.Title.Substring (index.ToString ().Length + 1);
 
-                if (top == Application.GetTopOverlappedChild () && topTitle == itemTitle)
+                if (top == ApplicationOverlapped.GetTopOverlappedChild () && topTitle == itemTitle)
                 {
                     item.Checked = true;
                 }
@@ -160,7 +160,7 @@ public class BackgroundWorkerCollection : Scenario
                     item.Checked = false;
                 }
 
-                item.Action += () => { Application.MoveToOverlappedChild (top); };
+                item.Action += () => { ApplicationOverlapped.MoveToOverlappedChild (top); };
                 menuItems.Add (item);
             }
 
@@ -188,7 +188,7 @@ public class BackgroundWorkerCollection : Scenario
         {
             List<MenuItem> menuItems = new ();
             var item = new MenuItem { Title = "WorkerApp", CheckType = MenuItemCheckStyle.Checked };
-            Toplevel top = Application.OverlappedChildren?.Find (x => x.Data.ToString () == "WorkerApp");
+            Toplevel top = ApplicationOverlapped.OverlappedChildren?.Find (x => x.Data.ToString () == "WorkerApp");
 
             if (top != null)
             {
@@ -197,16 +197,16 @@ public class BackgroundWorkerCollection : Scenario
 
             item.Action += () =>
                            {
-                               Toplevel top = Application.OverlappedChildren.Find (x => x.Data.ToString () == "WorkerApp");
+                               Toplevel top = ApplicationOverlapped.OverlappedChildren.Find (x => x.Data.ToString () == "WorkerApp");
                                item.Checked = top.Visible = (bool)!item.Checked;
 
                                if (top.Visible)
                                {
-                                   Application.MoveToOverlappedChild (top);
+                                   ApplicationOverlapped.MoveToOverlappedChild (top);
                                }
                                else
                                {
-                                   Application.OverlappedTop.SetNeedsDisplay ();
+                                   ApplicationOverlapped.OverlappedTop!.SetNeedsDisplay ();
                                }
                            };
             menuItems.Add (item);
@@ -373,14 +373,14 @@ public class BackgroundWorkerCollection : Scenario
         }
         private void WorkerApp_Closing (object sender, ToplevelClosingEventArgs e)
         {
-            Toplevel top = Application.OverlappedChildren.Find (x => x.Data.ToString () == "WorkerApp");
+            Toplevel top = ApplicationOverlapped.OverlappedChildren!.Find (x => x.Data.ToString () == "WorkerApp");
 
             if (Visible && top == this)
             {
                 Visible = false;
                 e.Cancel = true;
 
-                Application.OverlappedMoveNext ();
+                ApplicationOverlapped.OverlappedMoveNext ();
             }
         }
 
@@ -481,7 +481,7 @@ public class BackgroundWorkerCollection : Scenario
                                                  _stagingsUi.Add (stagingUI);
                                                  _stagingWorkers.Remove (staging);
 #if DEBUG_IDISPOSABLE
-                                                 if (Application.OverlappedTop is null)
+                                                 if (ApplicationOverlapped.OverlappedTop is null)
                                                  {
                                                      stagingUI.Dispose ();
                                                      return;
diff --git a/UnitTests/Application/ApplicationTests.cs b/UnitTests/Application/ApplicationTests.cs
index c600254a2..004f07e2e 100644
--- a/UnitTests/Application/ApplicationTests.cs
+++ b/UnitTests/Application/ApplicationTests.cs
@@ -89,12 +89,12 @@ public class ApplicationTests
 
         RunState runstate = null;
 
-        EventHandler<RunStateEventArgs> NewRunStateFn = (s, e) =>
+        EventHandler<RunStateEventArgs> newRunStateFn = (s, e) =>
                                                         {
                                                             Assert.NotNull (e.State);
                                                             runstate = e.State;
                                                         };
-        Application.NotifyNewRunState += NewRunStateFn;
+        Application.NotifyNewRunState += newRunStateFn;
 
         var topLevel = new Toplevel ();
         RunState rs = Application.Begin (topLevel);
@@ -105,7 +105,7 @@ public class ApplicationTests
         Assert.Equal (topLevel, Application.Top);
         Assert.Equal (topLevel, Application.Current);
 
-        Application.NotifyNewRunState -= NewRunStateFn;
+        Application.NotifyNewRunState -= newRunStateFn;
         Application.End (runstate);
 
         Assert.Null (Application.Current);
@@ -187,15 +187,15 @@ public class ApplicationTests
             Assert.Equal (Key.Empty, Application.AlternateBackwardKey);
             Assert.Equal (Key.Empty, Application.AlternateForwardKey);
             Assert.Equal (Key.Empty, Application.QuitKey);
-            Assert.Null (Application.OverlappedChildren);
-            Assert.Null (Application.OverlappedTop);
+            Assert.Null (ApplicationOverlapped.OverlappedChildren);
+            Assert.Null (ApplicationOverlapped.OverlappedTop);
 
             // Internal properties
             Assert.False (Application.IsInitialized);
             Assert.Equal (Application.GetSupportedCultures (), Application.SupportedCultures);
             Assert.False (Application._forceFakeConsole);
             Assert.Equal (-1, Application.MainThreadId);
-            Assert.Empty (Application._topLevels);
+            Assert.Empty (Application.TopLevels);
             Assert.Null (Application.MouseEnteredView);
 
             // Keyboard
@@ -235,8 +235,8 @@ public class ApplicationTests
         Application.QuitKey = Key.C;
         Application.KeyBindings.Add (Key.A, KeyBindingScope.Application, Command.Cancel);
 
-        //Application.OverlappedChildren = new List<View> ();
-        //Application.OverlappedTop = 
+        //ApplicationOverlapped.OverlappedChildren = new List<View> ();
+        //ApplicationOverlapped.OverlappedTop = 
         Application.MouseEnteredView = new ();
 
         //Application.WantContinuousButtonPressedView = new View ();
@@ -378,12 +378,12 @@ public class ApplicationTests
 
         RunState runstate = null;
 
-        EventHandler<RunStateEventArgs> NewRunStateFn = (s, e) =>
+        EventHandler<RunStateEventArgs> newRunStateFn = (s, e) =>
                                                         {
                                                             Assert.NotNull (e.State);
                                                             runstate = e.State;
                                                         };
-        Application.NotifyNewRunState += NewRunStateFn;
+        Application.NotifyNewRunState += newRunStateFn;
 
         RunState rs = Application.Begin (topLevel);
         Assert.NotNull (rs);
@@ -393,7 +393,7 @@ public class ApplicationTests
         Assert.Equal (topLevel, Application.Top);
         Assert.Equal (topLevel, Application.Current);
 
-        Application.NotifyNewRunState -= NewRunStateFn;
+        Application.NotifyNewRunState -= newRunStateFn;
         Application.End (runstate);
 
         Assert.Null (Application.Current);
@@ -419,7 +419,7 @@ public class ApplicationTests
         Assert.Equal (Application.Top, rs.Toplevel);
         Assert.Null (Application.MouseGrabView); // public
         Assert.Null (Application.WantContinuousButtonPressedView); // public
-        Assert.False (Application.MoveToOverlappedChild (Application.Top));
+        Assert.False (ApplicationOverlapped.MoveToOverlappedChild (Application.Top!));
         Application.Top.Dispose ();
     }
 
diff --git a/UnitTests/Views/OverlappedTests.cs b/UnitTests/Views/OverlappedTests.cs
index 2cf4fa96d..c1b0ec733 100644
--- a/UnitTests/Views/OverlappedTests.cs
+++ b/UnitTests/Views/OverlappedTests.cs
@@ -1,4 +1,5 @@
-using System.Threading;
+#nullable enable
+using System.Threading;
 using Xunit.Abstractions;
 
 namespace Terminal.Gui.ViewsTests;
@@ -30,25 +31,25 @@ public class OverlappedTests
 
         overlapped.Ready += (s, e) =>
                             {
-                                Assert.Empty (Application.OverlappedChildren);
+                                Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
                                 Application.Run (c1);
                             };
 
         c1.Ready += (s, e) =>
                     {
-                        Assert.Single (Application.OverlappedChildren);
+                        Assert.Single (ApplicationOverlapped.OverlappedChildren!);
                         Application.Run (c2);
                     };
 
         c2.Ready += (s, e) =>
                     {
-                        Assert.Equal (2, Application.OverlappedChildren.Count);
+                        Assert.Equal (2, ApplicationOverlapped.OverlappedChildren!.Count);
                         Application.Run (c3);
                     };
 
         c3.Ready += (s, e) =>
                     {
-                        Assert.Equal (3, Application.OverlappedChildren.Count);
+                        Assert.Equal (3, ApplicationOverlapped.OverlappedChildren!.Count);
                         c3.RequestStop ();
                         c2.RequestStop ();
                         c1.RequestStop ();
@@ -66,31 +67,31 @@ public class OverlappedTests
                                          Assert.False (Application.Current.Running);
 
                                          // But the Children order were reorder by Running = false
-                                         Assert.True (Application.OverlappedChildren [0] == c3);
-                                         Assert.True (Application.OverlappedChildren [1] == c2);
-                                         Assert.True (Application.OverlappedChildren [^1] == c1);
+                                         Assert.True (ApplicationOverlapped.OverlappedChildren! [0] == c3);
+                                         Assert.True (ApplicationOverlapped.OverlappedChildren [1] == c2);
+                                         Assert.True (ApplicationOverlapped.OverlappedChildren [^1] == c1);
                                      }
                                      else if (iterations == 2)
                                      {
                                          // The Current is c2 and Current.Running is false.
                                          Assert.True (Application.Current == c2);
                                          Assert.False (Application.Current.Running);
-                                         Assert.True (Application.OverlappedChildren [0] == c2);
-                                         Assert.True (Application.OverlappedChildren [^1] == c1);
+                                         Assert.True (ApplicationOverlapped.OverlappedChildren ![0] == c2);
+                                         Assert.True (ApplicationOverlapped.OverlappedChildren [^1] == c1);
                                      }
                                      else if (iterations == 1)
                                      {
                                          // The Current is c1 and Current.Running is false.
                                          Assert.True (Application.Current == c1);
                                          Assert.False (Application.Current.Running);
-                                         Assert.True (Application.OverlappedChildren [^1] == c1);
+                                         Assert.True (ApplicationOverlapped.OverlappedChildren! [^1] == c1);
                                      }
                                      else
                                      {
                                          // The Current is overlapped.
                                          Assert.True (Application.Current == overlapped);
                                          Assert.False (Application.Current.Running);
-                                         Assert.Empty (Application.OverlappedChildren);
+                                         Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
                                      }
 
                                      iterations--;
@@ -98,8 +99,8 @@ public class OverlappedTests
 
         Application.Run (overlapped);
 
-        Assert.Empty (Application.OverlappedChildren);
-        Assert.NotNull (Application.OverlappedTop);
+        Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
+        Assert.NotNull (ApplicationOverlapped.OverlappedTop);
         Assert.NotNull (Application.Top);
         overlapped.Dispose ();
     }
@@ -119,31 +120,31 @@ public class OverlappedTests
 
         top1.Ready += (s, e) =>
                       {
-                          Assert.Null (Application.OverlappedChildren);
+                          Assert.Null (ApplicationOverlapped.OverlappedChildren);
                           Application.Run (top2);
                       };
 
         top2.Ready += (s, e) =>
                       {
-                          Assert.Null (Application.OverlappedChildren);
+                          Assert.Null (ApplicationOverlapped.OverlappedChildren);
                           Application.Run (top3);
                       };
 
         top3.Ready += (s, e) =>
                       {
-                          Assert.Null (Application.OverlappedChildren);
+                          Assert.Null (ApplicationOverlapped.OverlappedChildren);
                           Application.Run (top4);
                       };
 
         top4.Ready += (s, e) =>
                       {
-                          Assert.Null (Application.OverlappedChildren);
+                          Assert.Null (ApplicationOverlapped.OverlappedChildren);
                           Application.Run (d);
                       };
 
         d.Ready += (s, e) =>
                    {
-                       Assert.Null (Application.OverlappedChildren);
+                       Assert.Null (ApplicationOverlapped.OverlappedChildren);
 
                        // This will close the d because on a not OverlappedContainer the Application.Current it always used.
                        Application.RequestStop (top1);
@@ -154,7 +155,7 @@ public class OverlappedTests
 
         Application.Iteration += (s, a) =>
                                  {
-                                     Assert.Null (Application.OverlappedChildren);
+                                     Assert.Null (ApplicationOverlapped.OverlappedChildren);
 
                                      if (iterations == 4)
                                      {
@@ -183,7 +184,7 @@ public class OverlappedTests
 
         Application.Run (top1);
 
-        Assert.Null (Application.OverlappedChildren);
+        Assert.Null (ApplicationOverlapped.OverlappedChildren);
         top1.Dispose ();
     }
 
@@ -261,37 +262,37 @@ public class OverlappedTests
 
         overlapped.Ready += (s, e) =>
                             {
-                                Assert.Empty (Application.OverlappedChildren);
+                                Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
                                 Application.Run (c1);
                             };
 
         c1.Ready += (s, e) =>
                     {
-                        Assert.Single (Application.OverlappedChildren);
+                        Assert.Single (ApplicationOverlapped.OverlappedChildren!);
                         Application.Run (c2);
                     };
 
         c2.Ready += (s, e) =>
                     {
-                        Assert.Equal (2, Application.OverlappedChildren.Count);
+                        Assert.Equal (2, ApplicationOverlapped.OverlappedChildren!.Count);
                         Application.Run (c3);
                     };
 
         c3.Ready += (s, e) =>
                     {
-                        Assert.Equal (3, Application.OverlappedChildren.Count);
+                        Assert.Equal (3, ApplicationOverlapped.OverlappedChildren!.Count);
                         Application.Run (d1);
                     };
 
         d1.Ready += (s, e) =>
                     {
-                        Assert.Equal (3, Application.OverlappedChildren.Count);
+                        Assert.Equal (3, ApplicationOverlapped.OverlappedChildren!.Count);
                         Application.Run (d2);
                     };
 
         d2.Ready += (s, e) =>
                     {
-                        Assert.Equal (3, Application.OverlappedChildren.Count);
+                        Assert.Equal (3, ApplicationOverlapped.OverlappedChildren!.Count);
                         Assert.True (Application.Current == d2);
                         Assert.True (Application.Current.Running);
 
@@ -326,11 +327,11 @@ public class OverlappedTests
                                      }
                                      else
                                      {
-                                         Assert.Equal (iterations, Application.OverlappedChildren.Count);
+                                         Assert.Equal (iterations, ApplicationOverlapped.OverlappedChildren!.Count);
 
                                          for (var i = 0; i < iterations; i++)
                                          {
-                                             Assert.Equal ((iterations - i + 1).ToString (), Application.OverlappedChildren [i].Id);
+                                             Assert.Equal ((iterations - i + 1).ToString (), ApplicationOverlapped.OverlappedChildren [i].Id);
                                          }
                                      }
 
@@ -339,8 +340,8 @@ public class OverlappedTests
 
         Application.Run (overlapped);
 
-        Assert.Empty (Application.OverlappedChildren);
-        Assert.NotNull (Application.OverlappedTop);
+        Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
+        Assert.NotNull (ApplicationOverlapped.OverlappedTop);
         Assert.NotNull (Application.Top);
         overlapped.Dispose ();
     }
@@ -363,37 +364,37 @@ public class OverlappedTests
 
         overlapped.Ready += (s, e) =>
                             {
-                                Assert.Empty (Application.OverlappedChildren);
+                                Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
                                 Application.Run (c1);
                             };
 
         c1.Ready += (s, e) =>
                     {
-                        Assert.Single (Application.OverlappedChildren);
+                        Assert.Single (ApplicationOverlapped.OverlappedChildren!);
                         Application.Run (c2);
                     };
 
         c2.Ready += (s, e) =>
                     {
-                        Assert.Equal (2, Application.OverlappedChildren.Count);
+                        Assert.Equal (2, ApplicationOverlapped.OverlappedChildren!.Count);
                         Application.Run (c3);
                     };
 
         c3.Ready += (s, e) =>
                     {
-                        Assert.Equal (3, Application.OverlappedChildren.Count);
+                        Assert.Equal (3, ApplicationOverlapped.OverlappedChildren!.Count);
                         Application.Run (d1);
                     };
 
         d1.Ready += (s, e) =>
                     {
-                        Assert.Equal (3, Application.OverlappedChildren.Count);
+                        Assert.Equal (3, ApplicationOverlapped.OverlappedChildren!.Count);
                         Application.Run (c4);
                     };
 
         c4.Ready += (s, e) =>
                     {
-                        Assert.Equal (4, Application.OverlappedChildren.Count);
+                        Assert.Equal (4, ApplicationOverlapped.OverlappedChildren!.Count);
 
                         // Trying to close the Dialog1
                         d1.RequestStop ();
@@ -415,13 +416,13 @@ public class OverlappedTests
                                      }
                                      else
                                      {
-                                         Assert.Equal (iterations, Application.OverlappedChildren.Count);
+                                         Assert.Equal (iterations, ApplicationOverlapped.OverlappedChildren!.Count);
 
                                          for (var i = 0; i < iterations; i++)
                                          {
                                              Assert.Equal (
                                                            (iterations - i + (iterations == 4 && i == 0 ? 2 : 1)).ToString (),
-                                                           Application.OverlappedChildren [i].Id
+                                                           ApplicationOverlapped.OverlappedChildren [i].Id
                                                           );
                                          }
                                      }
@@ -431,8 +432,8 @@ public class OverlappedTests
 
         Application.Run (overlapped);
 
-        Assert.Empty (Application.OverlappedChildren);
-        Assert.NotNull (Application.OverlappedTop);
+        Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
+        Assert.NotNull (ApplicationOverlapped.OverlappedTop);
         Assert.NotNull (Application.Top);
         overlapped.Dispose ();
     }
@@ -441,7 +442,7 @@ public class OverlappedTests
     [AutoInitShutdown]
     public void MoveCurrent_Returns_False_If_The_Current_And_Top_Parameter_Are_Both_With_Running_Set_To_False ()
     {
-        var overlapped = new Overlapped ();
+        Overlapped? overlapped = new Overlapped ();
         var c1 = new Toplevel ();
         var c2 = new Window ();
         var c3 = new Window ();
@@ -451,25 +452,25 @@ public class OverlappedTests
 
         overlapped.Ready += (s, e) =>
                             {
-                                Assert.Empty (Application.OverlappedChildren);
+                                Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
                                 Application.Run (c1);
                             };
 
         c1.Ready += (s, e) =>
                     {
-                        Assert.Single (Application.OverlappedChildren);
+                        Assert.Single (ApplicationOverlapped.OverlappedChildren!);
                         Application.Run (c2);
                     };
 
         c2.Ready += (s, e) =>
                     {
-                        Assert.Equal (2, Application.OverlappedChildren.Count);
+                        Assert.Equal (2, ApplicationOverlapped.OverlappedChildren!.Count);
                         Application.Run (c3);
                     };
 
         c3.Ready += (s, e) =>
                     {
-                        Assert.Equal (3, Application.OverlappedChildren.Count);
+                        Assert.Equal (3, ApplicationOverlapped.OverlappedChildren!.Count);
                         c3.RequestStop ();
                         c1.RequestStop ();
                     };
@@ -486,30 +487,30 @@ public class OverlappedTests
                                          Assert.False (Application.Current.Running);
 
                                          // But the Children order were reorder by Running = false
-                                         Assert.True (Application.OverlappedChildren [0] == c3);
-                                         Assert.True (Application.OverlappedChildren [1] == c1);
-                                         Assert.True (Application.OverlappedChildren [^1] == c2);
+                                         Assert.True (ApplicationOverlapped.OverlappedChildren! [0] == c3);
+                                         Assert.True (ApplicationOverlapped.OverlappedChildren [1] == c1);
+                                         Assert.True (ApplicationOverlapped.OverlappedChildren [^1] == c2);
                                      }
                                      else if (iterations == 2)
                                      {
                                          // The Current is c1 and Current.Running is false.
                                          Assert.True (Application.Current == c1);
                                          Assert.False (Application.Current.Running);
-                                         Assert.True (Application.OverlappedChildren [0] == c1);
-                                         Assert.True (Application.OverlappedChildren [^1] == c2);
+                                         Assert.True (ApplicationOverlapped.OverlappedChildren! [0] == c1);
+                                         Assert.True (ApplicationOverlapped.OverlappedChildren [^1] == c2);
                                      }
                                      else if (iterations == 1)
                                      {
                                          // The Current is c2 and Current.Running is false.
                                          Assert.True (Application.Current == c2);
                                          Assert.False (Application.Current.Running);
-                                         Assert.True (Application.OverlappedChildren [^1] == c2);
+                                         Assert.True (ApplicationOverlapped.OverlappedChildren! [^1] == c2);
                                      }
                                      else
                                      {
                                          // The Current is overlapped.
                                          Assert.True (Application.Current == overlapped);
-                                         Assert.Empty (Application.OverlappedChildren);
+                                         Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
                                      }
 
                                      iterations--;
@@ -517,8 +518,8 @@ public class OverlappedTests
 
         Application.Run (overlapped);
 
-        Assert.Empty (Application.OverlappedChildren);
-        Assert.NotNull (Application.OverlappedTop);
+        Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
+        Assert.NotNull (ApplicationOverlapped.OverlappedTop);
         Assert.NotNull (Application.Top);
         overlapped.Dispose ();
     }
@@ -526,7 +527,7 @@ public class OverlappedTests
     [Fact]
     public void MoveToOverlappedChild_Throw_NullReferenceException_Passing_Null_Parameter ()
     {
-        Assert.Throws<NullReferenceException> (delegate { Application.MoveToOverlappedChild (null); });
+        Assert.Throws<NullReferenceException> (delegate { ApplicationOverlapped.MoveToOverlappedChild (null); });
     }
 
     [Fact]
@@ -544,11 +545,11 @@ public class OverlappedTests
 
         overlapped.Ready += (s, e) =>
                             {
-                                Assert.Empty (Application.OverlappedChildren);
+                                Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
                                 Application.Run (logger);
                             };
 
-        logger.Ready += (s, e) => Assert.Single (Application.OverlappedChildren);
+        logger.Ready += (s, e) => Assert.Single (ApplicationOverlapped.OverlappedChildren!);
 
         Application.Iteration += (s, a) =>
                                  {
@@ -559,7 +560,7 @@ public class OverlappedTests
 
                                          stage.Ready += (s, e) =>
                                                         {
-                                                            Assert.Equal (iterations, Application.OverlappedChildren.Count);
+                                                            Assert.Equal (iterations, ApplicationOverlapped.OverlappedChildren!.Count);
                                                             stage.RequestStop ();
                                                         };
 
@@ -570,7 +571,7 @@ public class OverlappedTests
                                                                  allStageClosed = true;
                                                              }
 
-                                                             Assert.Equal (iterations, Application.OverlappedChildren.Count);
+                                                             Assert.Equal (iterations, ApplicationOverlapped.OverlappedChildren!.Count);
 
                                                              if (running)
                                                              {
@@ -581,7 +582,7 @@ public class OverlappedTests
                                                                  rpt.Ready += (s, e) =>
                                                                               {
                                                                                   iterations++;
-                                                                                  Assert.Equal (iterations, Application.OverlappedChildren.Count);
+                                                                                  Assert.Equal (iterations, ApplicationOverlapped.OverlappedChildren.Count);
                                                                               };
 
                                                                  Application.Run (rpt);
@@ -593,28 +594,28 @@ public class OverlappedTests
                                      else if (iterations == 11 && running)
                                      {
                                          running = false;
-                                         Assert.Equal (iterations, Application.OverlappedChildren.Count);
+                                         Assert.Equal (iterations, ApplicationOverlapped.OverlappedChildren!.Count);
                                      }
                                      else if (!overlappedRequestStop && running && !allStageClosed)
                                      {
-                                         Assert.Equal (iterations, Application.OverlappedChildren.Count);
+                                         Assert.Equal (iterations, ApplicationOverlapped.OverlappedChildren!.Count);
                                      }
                                      else if (!overlappedRequestStop && !running && allStageClosed)
                                      {
-                                         Assert.Equal (iterations, Application.OverlappedChildren.Count);
+                                         Assert.Equal (iterations, ApplicationOverlapped.OverlappedChildren!.Count);
                                          overlappedRequestStop = true;
-                                         overlapped.RequestStop ();
+                                         overlapped?.RequestStop ();
                                      }
                                      else
                                      {
-                                         Assert.Empty (Application.OverlappedChildren);
+                                         Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
                                      }
                                  };
 
         Application.Run (overlapped);
 
-        Assert.Empty (Application.OverlappedChildren);
-        Assert.NotNull (Application.OverlappedTop);
+        Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
+        Assert.NotNull (ApplicationOverlapped.OverlappedTop);
         Assert.NotNull (Application.Top);
         overlapped.Dispose ();
     }
@@ -652,32 +653,32 @@ public class OverlappedTests
 
         overlapped.Ready += (s, e) =>
                             {
-                                Assert.Empty (Application.OverlappedChildren);
+                                Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
                                 Application.Run (c1);
                             };
 
         c1.Ready += (s, e) =>
                     {
-                        Assert.Single (Application.OverlappedChildren);
+                        Assert.Single (ApplicationOverlapped.OverlappedChildren!);
                         Application.Run (c2);
                     };
 
         c2.Ready += (s, e) =>
                     {
-                        Assert.Equal (2, Application.OverlappedChildren.Count);
+                        Assert.Equal (2, ApplicationOverlapped.OverlappedChildren!.Count);
                         Application.Run (c3);
                     };
 
         c3.Ready += (s, e) =>
                     {
-                        Assert.Equal (3, Application.OverlappedChildren.Count);
+                        Assert.Equal (3, ApplicationOverlapped.OverlappedChildren!.Count);
                         Application.Run (d);
                     };
 
         // Also easy because the Overlapped Container handles all at once
         d.Ready += (s, e) =>
                    {
-                       Assert.Equal (3, Application.OverlappedChildren.Count);
+                       Assert.Equal (3, ApplicationOverlapped.OverlappedChildren!.Count);
 
                        // This will not close the OverlappedContainer because d is a modal Toplevel
                        Application.RequestStop (overlapped);
@@ -696,11 +697,11 @@ public class OverlappedTests
                                      }
                                      else
                                      {
-                                         Assert.Equal (iterations, Application.OverlappedChildren.Count);
+                                         Assert.Equal (iterations, ApplicationOverlapped.OverlappedChildren!.Count);
 
                                          for (var i = 0; i < iterations; i++)
                                          {
-                                             Assert.Equal ((iterations - i + 1).ToString (), Application.OverlappedChildren [i].Id);
+                                             Assert.Equal ((iterations - i + 1).ToString (), ApplicationOverlapped.OverlappedChildren [i].Id);
                                          }
                                      }
 
@@ -709,8 +710,8 @@ public class OverlappedTests
 
         Application.Run (overlapped);
 
-        Assert.Empty (Application.OverlappedChildren);
-        Assert.NotNull (Application.OverlappedTop);
+        Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
+        Assert.NotNull (ApplicationOverlapped.OverlappedTop);
         Assert.NotNull (Application.Top);
         overlapped.Dispose ();
     }
@@ -731,32 +732,32 @@ public class OverlappedTests
 
         overlapped.Ready += (s, e) =>
                             {
-                                Assert.Empty (Application.OverlappedChildren);
+                                Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
                                 Application.Run (c1);
                             };
 
         c1.Ready += (s, e) =>
                     {
-                        Assert.Single (Application.OverlappedChildren);
+                        Assert.Single (ApplicationOverlapped.OverlappedChildren!);
                         Application.Run (c2);
                     };
 
         c2.Ready += (s, e) =>
                     {
-                        Assert.Equal (2, Application.OverlappedChildren.Count);
+                        Assert.Equal (2, ApplicationOverlapped.OverlappedChildren!.Count);
                         Application.Run (c3);
                     };
 
         c3.Ready += (s, e) =>
                     {
-                        Assert.Equal (3, Application.OverlappedChildren.Count);
+                        Assert.Equal (3, ApplicationOverlapped.OverlappedChildren!.Count);
                         Application.Run (d);
                     };
 
         //More harder because it's sequential.
         d.Ready += (s, e) =>
                    {
-                       Assert.Equal (3, Application.OverlappedChildren.Count);
+                       Assert.Equal (3, ApplicationOverlapped.OverlappedChildren!.Count);
 
                        // Close the Dialog
                        Application.RequestStop ();
@@ -776,11 +777,11 @@ public class OverlappedTests
                                      }
                                      else
                                      {
-                                         Assert.Equal (iterations, Application.OverlappedChildren.Count);
+                                         Assert.Equal (iterations, ApplicationOverlapped.OverlappedChildren!.Count);
 
                                          for (var i = 0; i < iterations; i++)
                                          {
-                                             Assert.Equal ((iterations - i + 1).ToString (), Application.OverlappedChildren [i].Id);
+                                             Assert.Equal ((iterations - i + 1).ToString (), ApplicationOverlapped.OverlappedChildren [i].Id);
                                          }
                                      }
 
@@ -789,8 +790,8 @@ public class OverlappedTests
 
         Application.Run (overlapped);
 
-        Assert.Empty (Application.OverlappedChildren);
-        Assert.NotNull (Application.OverlappedTop);
+        Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
+        Assert.NotNull (ApplicationOverlapped.OverlappedTop);
         Assert.NotNull (Application.Top);
         overlapped.Dispose ();
     }
@@ -811,32 +812,32 @@ public class OverlappedTests
 
         overlapped.Ready += (s, e) =>
                             {
-                                Assert.Empty (Application.OverlappedChildren);
+                                Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
                                 Application.Run (c1);
                             };
 
         c1.Ready += (s, e) =>
                     {
-                        Assert.Single (Application.OverlappedChildren);
+                        Assert.Single (ApplicationOverlapped.OverlappedChildren!);
                         Application.Run (c2);
                     };
 
         c2.Ready += (s, e) =>
                     {
-                        Assert.Equal (2, Application.OverlappedChildren.Count);
+                        Assert.Equal (2, ApplicationOverlapped.OverlappedChildren!.Count);
                         Application.Run (c3);
                     };
 
         c3.Ready += (s, e) =>
                     {
-                        Assert.Equal (3, Application.OverlappedChildren.Count);
+                        Assert.Equal (3, ApplicationOverlapped.OverlappedChildren!.Count);
                         Application.Run (d);
                     };
 
         // More easy because the Overlapped Container handles all at once
         d.Ready += (s, e) =>
                    {
-                       Assert.Equal (3, Application.OverlappedChildren.Count);
+                       Assert.Equal (3, ApplicationOverlapped.OverlappedChildren!.Count);
 
                        // This will not close the OverlappedContainer because d is a modal Toplevel and will be closed.
                        overlapped.RequestStop ();
@@ -855,11 +856,11 @@ public class OverlappedTests
                                      }
                                      else
                                      {
-                                         Assert.Equal (iterations, Application.OverlappedChildren.Count);
+                                         Assert.Equal (iterations, ApplicationOverlapped.OverlappedChildren!.Count);
 
                                          for (var i = 0; i < iterations; i++)
                                          {
-                                             Assert.Equal ((iterations - i + 1).ToString (), Application.OverlappedChildren [i].Id);
+                                             Assert.Equal ((iterations - i + 1).ToString (), ApplicationOverlapped.OverlappedChildren [i].Id);
                                          }
                                      }
 
@@ -868,8 +869,8 @@ public class OverlappedTests
 
         Application.Run (overlapped);
 
-        Assert.Empty (Application.OverlappedChildren);
-        Assert.NotNull (Application.OverlappedTop);
+        Assert.Empty (ApplicationOverlapped.OverlappedChildren!);
+        Assert.NotNull (ApplicationOverlapped.OverlappedTop);
         Assert.NotNull (Application.Top);
         overlapped.Dispose ();
     }
@@ -885,7 +886,7 @@ public class OverlappedTests
         RunState rsOverlapped = Application.Begin (overlapped);
 
         // Need to fool MainLoop into thinking it's running
-        Application.MainLoop.Running = true;
+        Application.MainLoop!.Running = true;
 
         // RunIteration must be call on each iteration because
         // it's using the Begin and not the Run method
@@ -894,7 +895,7 @@ public class OverlappedTests
 
         Assert.Equal (overlapped, rsOverlapped.Toplevel);
         Assert.Equal (Application.Top, rsOverlapped.Toplevel);
-        Assert.Equal (Application.OverlappedTop, rsOverlapped.Toplevel);
+        Assert.Equal (ApplicationOverlapped.OverlappedTop, rsOverlapped.Toplevel);
         Assert.Equal (Application.Current, rsOverlapped.Toplevel);
         Assert.Equal (overlapped, Application.Current);
 
@@ -903,7 +904,7 @@ public class OverlappedTests
 
         Assert.Equal (overlapped, rsOverlapped.Toplevel);
         Assert.Equal (Application.Top, rsOverlapped.Toplevel);
-        Assert.Equal (Application.OverlappedTop, rsOverlapped.Toplevel);
+        Assert.Equal (ApplicationOverlapped.OverlappedTop, rsOverlapped.Toplevel);
         // The win1 Visible is false and cannot be set as the Current
         Assert.Equal (Application.Current, rsOverlapped.Toplevel);
         Assert.Equal (overlapped, Application.Current);
@@ -916,7 +917,7 @@ public class OverlappedTests
         // and not the original overlapped
         Assert.Equal (win2, rsOverlapped.Toplevel);
         Assert.Equal (Application.Top, overlapped);
-        Assert.Equal (Application.OverlappedTop, overlapped);
+        Assert.Equal (ApplicationOverlapped.OverlappedTop, overlapped);
         Assert.Equal (Application.Current, rsWin2.Toplevel);
         Assert.Equal (win2, Application.Current);
         Assert.Equal (win1, rsWin1.Toplevel);
@@ -931,7 +932,7 @@ public class OverlappedTests
 
         Assert.Equal (win2, rsOverlapped.Toplevel);
         Assert.Equal (Application.Top, overlapped);
-        Assert.Equal (Application.OverlappedTop, overlapped);
+        Assert.Equal (ApplicationOverlapped.OverlappedTop, overlapped);
         Assert.Equal (Application.Current, rsWin2.Toplevel);
         Assert.Equal (win2, Application.Current);
         Assert.Equal (win1, rsWin1.Toplevel);
@@ -945,7 +946,7 @@ public class OverlappedTests
 
         Assert.Equal (win2, rsOverlapped.Toplevel);
         Assert.Equal (Application.Top, overlapped);
-        Assert.Equal (Application.OverlappedTop, overlapped);
+        Assert.Equal (ApplicationOverlapped.OverlappedTop, overlapped);
         Assert.Equal (Application.Current, rsWin2.Toplevel);
         Assert.Equal (win2, Application.Current);
         Assert.Equal (win1, rsWin1.Toplevel);
@@ -963,7 +964,7 @@ public class OverlappedTests
 #endif
         Assert.Null (rsOverlapped.Toplevel);
         Assert.Equal (Application.Top, overlapped);
-        Assert.Equal (Application.OverlappedTop, overlapped);
+        Assert.Equal (ApplicationOverlapped.OverlappedTop, overlapped);
         Assert.Equal (Application.Current, rsWin1.Toplevel);
         Assert.Equal (win1, Application.Current);
         Assert.Equal (win1, rsWin1.Toplevel);
@@ -978,7 +979,7 @@ public class OverlappedTests
 #endif
         Assert.Null (rsOverlapped.Toplevel);
         Assert.Equal (Application.Top, overlapped);
-        Assert.Equal (Application.OverlappedTop, overlapped);
+        Assert.Equal (ApplicationOverlapped.OverlappedTop, overlapped);
         Assert.Equal (Application.Current, overlapped);
         Assert.Null (rsWin1.Toplevel);
         // See here that the only Toplevel that needs to End is the overlapped
@@ -994,7 +995,7 @@ public class OverlappedTests
 #endif
         Assert.Null (rsOverlapped.Toplevel);
         Assert.Equal (Application.Top, overlapped);
-        Assert.Equal (Application.OverlappedTop, overlapped);
+        Assert.Equal (ApplicationOverlapped.OverlappedTop, overlapped);
         Assert.Null (Application.Current);
         Assert.Null (rsWin1.Toplevel);
         Assert.Null (rsWin2.Toplevel);
@@ -1021,10 +1022,10 @@ public class OverlappedTests
     public void KeyBindings_Command_With_OverlappedTop ()
     {
         Toplevel top = new ();
-        Assert.Null (Application.OverlappedTop);
+        Assert.Null (ApplicationOverlapped.OverlappedTop);
         top.IsOverlappedContainer = true;
         Application.Begin (top);
-        Assert.Equal (Application.Top, Application.OverlappedTop);
+        Assert.Equal (Application.Top, ApplicationOverlapped.OverlappedTop);
 
         var isRunning = true;
 
@@ -1060,7 +1061,7 @@ public class OverlappedTests
         Assert.Null (top.Focused);
         Assert.Equal (top, Application.Current);
         Assert.True (top.IsCurrentTop);
-        Assert.Equal (top, Application.OverlappedTop);
+        Assert.Equal (top, ApplicationOverlapped.OverlappedTop);
         Application.Begin (win1);
         Assert.Equal (new (0, 0, 40, 25), win1.Frame);
         Assert.NotEqual (top, Application.Current);
@@ -1072,7 +1073,7 @@ public class OverlappedTests
         Assert.Null (top.MostFocused);
         Assert.Equal (tf1W1, win1.MostFocused);
         Assert.True (win1.IsOverlapped);
-        Assert.Single (Application.OverlappedChildren);
+        Assert.Single (ApplicationOverlapped.OverlappedChildren!);
         Application.Begin (win2);
         Assert.Equal (new (0, 0, 40, 25), win2.Frame);
         Assert.NotEqual (top, Application.Current);
@@ -1083,16 +1084,16 @@ public class OverlappedTests
         Assert.Null (top.Focused);
         Assert.Null (top.MostFocused);
         Assert.Equal (tf1W2, win2.MostFocused);
-        Assert.Equal (2, Application.OverlappedChildren.Count);
+        Assert.Equal (2, ApplicationOverlapped.OverlappedChildren!.Count);
 
-        Application.MoveToOverlappedChild (win1);
+        ApplicationOverlapped.MoveToOverlappedChild (win1);
         Assert.Equal (win1, Application.Current);
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
         win1.Running = true;
         Assert.True (Application.OnKeyDown (Application.QuitKey));
         Assert.False (isRunning);
         Assert.False (win1.Running);
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
 
         Assert.True (
                      Application.OnKeyDown (Key.Z.WithCtrl)
@@ -1110,77 +1111,77 @@ public class OverlappedTests
         Assert.Equal ($"First line Win1{Environment.NewLine}Second line Win1", tvW1.Text);
 
         Assert.True (Application.OnKeyDown (Key.Tab.WithCtrl));    // move to win2
-        Assert.Equal (win2, Application.OverlappedChildren [0]);
+        Assert.Equal (win2, ApplicationOverlapped.OverlappedChildren [0]);
 
         Assert.True (Application.OnKeyDown (Key.Tab.WithCtrl.WithShift));    // move back to win1
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
 
         Assert.Equal (tvW1, win1.MostFocused);
         Assert.True (Application.OnKeyDown (Key.Tab));    // text view eats tab
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
         Assert.Equal (tvW1, win1.MostFocused);
 
         tvW1.AllowsTab = false;
         Assert.True (Application.OnKeyDown (Key.Tab));    // text view eats tab
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
         Assert.Equal (tf2W1, win1.MostFocused);
 
         Assert.True (Application.OnKeyDown (Key.CursorRight));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
         Assert.Equal (tf2W1, win1.MostFocused);
         Assert.True (Application.OnKeyDown (Key.CursorDown));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
         Assert.Equal (tf1W1, win1.MostFocused);
 #if UNIX_KEY_BINDINGS
-        Assert.True (Application.OverlappedChildren [0].ProcessKeyDown (new (Key.I.WithCtrl)));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.True (ApplicationOverlapped.OverlappedChildren [0].ProcessKeyDown (new (Key.I.WithCtrl)));
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
         Assert.Equal (tf2W1, win1.MostFocused);
 #endif
         Assert.True (Application.OnKeyDown (Key.Tab));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
         Assert.Equal (tvW1, win1.MostFocused);
         Assert.True (Application.OnKeyDown (Key.CursorLeft));  // The view to the left of tvW1 is tf2W1, but tvW1 is still focused and eats cursor keys
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
         Assert.Equal (tvW1, win1.MostFocused);
         Assert.True (Application.OnKeyDown (Key.CursorUp));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
         Assert.Equal (tvW1, win1.MostFocused);
         Assert.True (Application.OnKeyDown (Key.Tab));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
         Assert.Equal (tf2W1, win1.MostFocused);
 
         Assert.True (Application.OnKeyDown (Key.Tab.WithCtrl)); // Move to win2
-        Assert.Equal (win2, Application.OverlappedChildren [0]);
+        Assert.Equal (win2, ApplicationOverlapped.OverlappedChildren [0]);
         Assert.Equal (tf1W2, win2.MostFocused);
         tf2W2.SetFocus ();
         Assert.True (tf2W2.HasFocus);
 
         Assert.True (Application.OnKeyDown (Key.Tab.WithCtrl.WithShift));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
         Assert.Equal (tf2W1, win1.MostFocused);
         Assert.True (Application.OnKeyDown (Application.AlternateForwardKey));
-        Assert.Equal (win2, Application.OverlappedChildren [0]);
+        Assert.Equal (win2, ApplicationOverlapped.OverlappedChildren [0]);
         Assert.Equal (tf2W2, win2.MostFocused);
         Assert.True (Application.OnKeyDown (Application.AlternateBackwardKey));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
         Assert.Equal (tf2W1, win1.MostFocused);
         Assert.True (Application.OnKeyDown (Key.CursorDown));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
         Assert.Equal (tf1W1, win1.MostFocused);
 #if UNIX_KEY_BINDINGS
         Assert.True (Application.OnKeyDown (new (Key.B.WithCtrl)));
 #else
         Assert.True (Application.OnKeyDown (Key.CursorLeft));
 #endif
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
         Assert.Equal (tf1W1, win1.MostFocused);
         Assert.True (Application.OnKeyDown (Key.CursorDown));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
         Assert.Equal (tvW1, win1.MostFocused);
         Assert.Equal (Point.Empty, tvW1.CursorPosition);
 
         Assert.True (Application.OnKeyDown (Key.End.WithCtrl));
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
         Assert.Equal (tvW1, win1.MostFocused);
         Assert.Equal (new (16, 1), tvW1.CursorPosition);
 #if UNIX_KEY_BINDINGS
@@ -1188,11 +1189,11 @@ public class OverlappedTests
 #else
         Assert.True (Application.OnKeyDown (Key.CursorRight));
 #endif
-        Assert.Equal (win1, Application.OverlappedChildren [0]);
+        Assert.Equal (win1, ApplicationOverlapped.OverlappedChildren [0]);
         Assert.Equal (tvW1, win1.MostFocused);
 
 #if UNIX_KEY_BINDINGS
-        Assert.True (Application.OverlappedChildren [0].ProcessKeyDown (new (Key.L.WithCtrl)));
+        Assert.True (ApplicationOverlapped.OverlappedChildren [0].ProcessKeyDown (new (Key.L.WithCtrl)));
 #endif
         win2.Dispose ();
         win1.Dispose ();

From cb3e80666f645c7ca31e0a98e7af9e03f4068fd9 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Wed, 24 Jul 2024 15:43:35 -0600
Subject: [PATCH 25/33] Moved Overlapped stuff to ApplicationOverlap static
 class. Fixed nullable warnings.

---
 Terminal.Gui/Application/Application.Overlapped.cs | 6 ++----
 UnitTests/Views/OverlappedTests.cs                 | 2 +-
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/Terminal.Gui/Application/Application.Overlapped.cs b/Terminal.Gui/Application/Application.Overlapped.cs
index ce88c1567..cf9212d80 100644
--- a/Terminal.Gui/Application/Application.Overlapped.cs
+++ b/Terminal.Gui/Application/Application.Overlapped.cs
@@ -106,10 +106,8 @@ public static class ApplicationOverlapped
     /// <returns></returns>
     public static bool MoveToOverlappedChild (Toplevel? top)
     {
-        if (top is null)
-        {
-            return false;
-        }
+        ArgumentNullException.ThrowIfNull (top);
+
         if (top.Visible && OverlappedTop is { } && Application.Current?.Modal == false)
         {
             lock (Application.TopLevels)
diff --git a/UnitTests/Views/OverlappedTests.cs b/UnitTests/Views/OverlappedTests.cs
index c1b0ec733..91555ca91 100644
--- a/UnitTests/Views/OverlappedTests.cs
+++ b/UnitTests/Views/OverlappedTests.cs
@@ -527,7 +527,7 @@ public class OverlappedTests
     [Fact]
     public void MoveToOverlappedChild_Throw_NullReferenceException_Passing_Null_Parameter ()
     {
-        Assert.Throws<NullReferenceException> (delegate { ApplicationOverlapped.MoveToOverlappedChild (null); });
+        Assert.Throws<ArgumentNullException> (delegate { ApplicationOverlapped.MoveToOverlappedChild (null); });
     }
 
     [Fact]

From cbecae5d47aea31611137cd060679e6445b6830c Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Wed, 24 Jul 2024 15:48:41 -0600
Subject: [PATCH 26/33] Moved Overlapped stuff to ApplicationOverlap static
 class. Fixed nullable warnings.

---
 Terminal.Gui/Application/Application.Navigation.cs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Terminal.Gui/Application/Application.Navigation.cs b/Terminal.Gui/Application/Application.Navigation.cs
index 44bc6e99a..fde03913b 100644
--- a/Terminal.Gui/Application/Application.Navigation.cs
+++ b/Terminal.Gui/Application/Application.Navigation.cs
@@ -1,6 +1,9 @@
 #nullable enable
 namespace Terminal.Gui;
 
+/// <summary>
+///     Helper class for <see cref="Application"/> navigation.
+/// </summary>
 internal static class ApplicationNavigation
 {
     /// <summary>

From 331d9726d7210578dfb195f1c4d5886288dc42cf Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Wed, 24 Jul 2024 16:18:20 -0600
Subject: [PATCH 27/33] nullable enable TopLevel

---
 .../Application/Application.Overlapped.cs     | 21 +++++-
 Terminal.Gui/Application/Application.Run.cs   |  2 +-
 Terminal.Gui/View/Layout/ViewLayout.cs        |  2 +-
 Terminal.Gui/Views/Toplevel.cs                | 73 +++++++++++--------
 Terminal.Gui/Views/ToplevelOverlapped.cs      |  3 -
 UICatalog/UICatalog.cs                        |  6 +-
 UnitTests/Views/OverlappedTests.cs            | 16 ++--
 UnitTests/Views/ToplevelTests.cs              |  2 +-
 8 files changed, 72 insertions(+), 53 deletions(-)

diff --git a/Terminal.Gui/Application/Application.Overlapped.cs b/Terminal.Gui/Application/Application.Overlapped.cs
index cf9212d80..8ae645717 100644
--- a/Terminal.Gui/Application/Application.Overlapped.cs
+++ b/Terminal.Gui/Application/Application.Overlapped.cs
@@ -1,4 +1,6 @@
 #nullable enable
+using System.Reflection;
+
 namespace Terminal.Gui;
 
 /// <summary>
@@ -6,6 +8,17 @@ namespace Terminal.Gui;
 /// </summary>
 public static class ApplicationOverlapped
 {
+
+    /// <summary>
+    ///     Gets or sets if <paramref name="top"/> is in overlapped mode within a Toplevel container.
+    /// </summary>
+    /// <param name="top"></param>
+    /// <returns></returns>
+    public static bool IsOverlapped (Toplevel? top)
+    {
+        return ApplicationOverlapped.OverlappedTop is { } && ApplicationOverlapped.OverlappedTop != top && !top!.Modal;
+    }
+
     /// <summary>
     ///     Gets the list of the Overlapped children which are not modal <see cref="Toplevel"/> from the
     ///     <see cref="OverlappedTop"/>.
@@ -99,7 +112,7 @@ public static class ApplicationOverlapped
     }
 
     /// <summary>
-    ///     Move to the next Overlapped child from the <see cref="OverlappedTop"/> and set it as the <see cref="Top"/> if
+    ///     Move to the next Overlapped child from the <see cref="OverlappedTop"/> and set it as the <see cref="Application.Top"/> if
     ///     it is not already.
     /// </summary>
     /// <param name="top"></param>
@@ -262,7 +275,7 @@ public static class ApplicationOverlapped
     }
 
     /// <summary>
-    ///     Given <paramref name="view"/>, returns the first Superview up the chain that is <see cref="Top"/>.
+    ///     Given <paramref name="view"/>, returns the first Superview up the chain that is <see cref="Application.Top"/>.
     /// </summary>
     internal static View? FindTopFromView (View? view)
     {
@@ -284,7 +297,7 @@ public static class ApplicationOverlapped
     }
 
     /// <summary>
-    ///     If the <see cref="Current"/> is not the <paramref name="top"/> then <paramref name="top"/> is moved to the top of
+    ///     If the <see cref="Application.Current"/> is not the <paramref name="top"/> then <paramref name="top"/> is moved to the top of
     ///     the Toplevel stack and made Current.
     /// </summary>
     /// <param name="top"></param>
@@ -361,7 +374,7 @@ public static class ApplicationOverlapped
         {
             lock (Application.TopLevels)
             {
-                Application.TopLevels.MoveTo (top, 0, new ToplevelEqualityComparer ());
+                Application.TopLevels.MoveTo (top!, 0, new ToplevelEqualityComparer ());
                 Application.Current = top;
             }
         }
diff --git a/Terminal.Gui/Application/Application.Run.cs b/Terminal.Gui/Application/Application.Run.cs
index 3e088c348..57097cbda 100644
--- a/Terminal.Gui/Application/Application.Run.cs
+++ b/Terminal.Gui/Application/Application.Run.cs
@@ -579,7 +579,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
             {
                 ApplicationOverlapped.OverlappedTop?.OnDeactivate (state.Toplevel);
                 state.Toplevel = Current;
-                ApplicationOverlapped.OverlappedTop?.OnActivate (state.Toplevel);
+                ApplicationOverlapped.OverlappedTop?.OnActivate (state.Toplevel!);
                 Top!.SetSubViewNeedsDisplay ();
                 Refresh ();
             }
diff --git a/Terminal.Gui/View/Layout/ViewLayout.cs b/Terminal.Gui/View/Layout/ViewLayout.cs
index 4e2531745..72a9bf14c 100644
--- a/Terminal.Gui/View/Layout/ViewLayout.cs
+++ b/Terminal.Gui/View/Layout/ViewLayout.cs
@@ -404,7 +404,7 @@ public partial class View
         int targetY,
         out int nx,
         out int ny,
-        out StatusBar statusBar
+        out StatusBar? statusBar
     )
     {
         int maxDimension;
diff --git a/Terminal.Gui/Views/Toplevel.cs b/Terminal.Gui/Views/Toplevel.cs
index d13ae0766..26fe724c8 100644
--- a/Terminal.Gui/Views/Toplevel.cs
+++ b/Terminal.Gui/Views/Toplevel.cs
@@ -1,3 +1,4 @@
+#nullable enable
 namespace Terminal.Gui;
 
 /// <summary>
@@ -60,7 +61,7 @@ public partial class Toplevel : View
     /// </summary>
     public bool Modal { get; set; }
 
-    private void Toplevel_MouseClick (object sender, MouseEventEventArgs e) { e.Handled = InvokeCommand (Command.HotKey) == true; }
+    private void Toplevel_MouseClick (object? sender, MouseEventEventArgs e) { e.Handled = InvokeCommand (Command.HotKey) == true; }
 
     #endregion
 
@@ -68,11 +69,11 @@ public partial class Toplevel : View
 
     // TODO: Deprecate - Any view can host a menubar in v2
     /// <summary>Gets or sets the menu for this Toplevel.</summary>
-    public virtual MenuBar MenuBar { get; set; }
+    public MenuBar? MenuBar { get; set; }
 
     // TODO: Deprecate - Any view can host a statusbar in v2
     /// <summary>Gets or sets the status bar for this Toplevel.</summary>
-    public virtual StatusBar StatusBar { get; set; }
+    public StatusBar? StatusBar { get; set; }
 
     /// <inheritdoc/>
     public override View Add (View view)
@@ -141,22 +142,22 @@ public partial class Toplevel : View
     ///     Invoked when the last child of the Toplevel <see cref="RunState"/> is closed from by
     ///     <see cref="Application.End(RunState)"/>.
     /// </summary>
-    public event EventHandler AllChildClosed;
+    public event EventHandler? AllChildClosed;
 
     // TODO: Overlapped - Rename to *Subviews* - Move to View?
     /// <summary>
     ///     Invoked when a child of the Toplevel <see cref="RunState"/> is closed by
     ///     <see cref="Application.End(RunState)"/>.
     /// </summary>
-    public event EventHandler<ToplevelEventArgs> ChildClosed;
+    public event EventHandler<ToplevelEventArgs>? ChildClosed;
 
     // TODO: Overlapped - Rename to *Subviews* - Move to View?
     /// <summary>Invoked when a child Toplevel's <see cref="RunState"/> has been loaded.</summary>
-    public event EventHandler<ToplevelEventArgs> ChildLoaded;
+    public event EventHandler<ToplevelEventArgs>? ChildLoaded;
 
     // TODO: Overlapped - Rename to *Subviews* - Move to View?
     /// <summary>Invoked when a cjhild Toplevel's <see cref="RunState"/> has been unloaded.</summary>
-    public event EventHandler<ToplevelEventArgs> ChildUnloaded;
+    public event EventHandler<ToplevelEventArgs>? ChildUnloaded;
 
     #endregion
 
@@ -176,26 +177,26 @@ public partial class Toplevel : View
 
     // TODO: IRunnable: Re-implement as an event on IRunnable; IRunnable.Activating/Activate
     /// <summary>Invoked when the Toplevel <see cref="RunState"/> becomes the <see cref="Application.Current"/> Toplevel.</summary>
-    public event EventHandler<ToplevelEventArgs> Activate;
+    public event EventHandler<ToplevelEventArgs>? Activate;
 
     // TODO: IRunnable: Re-implement as an event on IRunnable; IRunnable.Deactivating/Deactivate?
     /// <summary>Invoked when the Toplevel<see cref="RunState"/> ceases to be the <see cref="Application.Current"/> Toplevel.</summary>
-    public event EventHandler<ToplevelEventArgs> Deactivate;
+    public event EventHandler<ToplevelEventArgs>? Deactivate;
 
     /// <summary>Invoked when the Toplevel's <see cref="RunState"/> is closed by <see cref="Application.End(RunState)"/>.</summary>
-    public event EventHandler<ToplevelEventArgs> Closed;
+    public event EventHandler<ToplevelEventArgs>? Closed;
 
     /// <summary>
     ///     Invoked when the Toplevel's <see cref="RunState"/> is being closed by
     ///     <see cref="Application.RequestStop(Toplevel)"/>.
     /// </summary>
-    public event EventHandler<ToplevelClosingEventArgs> Closing;
+    public event EventHandler<ToplevelClosingEventArgs>? Closing;
 
     /// <summary>
     ///     Invoked when the <see cref="Toplevel"/> <see cref="RunState"/> has begun to be loaded. A Loaded event handler
     ///     is a good place to finalize initialization before calling <see cref="Application.RunLoop(RunState)"/>.
     /// </summary>
-    public event EventHandler Loaded;
+    public event EventHandler? Loaded;
 
     /// <summary>
     ///     Called from <see cref="Application.Begin(Toplevel)"/> before the <see cref="Toplevel"/> redraws for the first
@@ -209,8 +210,9 @@ public partial class Toplevel : View
     {
         IsLoaded = true;
 
-        foreach (Toplevel tl in Subviews.Where (v => v is Toplevel))
+        foreach (var view in Subviews.Where (v => v is Toplevel))
         {
+            var tl = (Toplevel)view;
             tl.OnLoaded ();
         }
 
@@ -225,7 +227,7 @@ public partial class Toplevel : View
     ///         <see cref="Application.Run(Toplevel, Func{Exception, bool})"/> on this <see cref="Toplevel"/>.
     ///     </para>
     /// </summary>
-    public event EventHandler Ready;
+    public event EventHandler? Ready;
 
     /// <summary>
     ///     Stops and closes this <see cref="Toplevel"/>. If this Toplevel is the top-most Toplevel,
@@ -288,7 +290,7 @@ public partial class Toplevel : View
     ///     Invoked when the Toplevel <see cref="RunState"/> has been unloaded. A Unloaded event handler is a good place
     ///     to dispose objects after calling <see cref="Application.End(RunState)"/>.
     /// </summary>
-    public event EventHandler Unloaded;
+    public event EventHandler? Unloaded;
 
     internal virtual void OnActivate (Toplevel deactivated) { Activate?.Invoke (this, new (deactivated)); }
 
@@ -331,8 +333,9 @@ public partial class Toplevel : View
     /// </summary>
     internal virtual void OnReady ()
     {
-        foreach (Toplevel tl in Subviews.Where (v => v is Toplevel))
+        foreach (var view in Subviews.Where (v => v is Toplevel))
         {
+            var tl = (Toplevel)view;
             tl.OnReady ();
         }
 
@@ -342,8 +345,9 @@ public partial class Toplevel : View
     /// <summary>Called from <see cref="Application.End(RunState)"/> before the <see cref="Toplevel"/> is disposed.</summary>
     internal virtual void OnUnloaded ()
     {
-        foreach (Toplevel tl in Subviews.Where (v => v is Toplevel))
+        foreach (var view in Subviews.Where (v => v is Toplevel))
         {
+            var tl = (Toplevel)view;
             tl.OnUnloaded ();
         }
 
@@ -411,7 +415,7 @@ public partial class Toplevel : View
 
     /// <inheritdoc/>
     public override bool OnLeave (View view) { return MostFocused?.OnLeave (view) ?? base.OnLeave (view); }
-    
+
     #endregion
 
     #region Size / Position Management
@@ -458,15 +462,20 @@ public partial class Toplevel : View
     ///     implementation of specific positions for inherited <see cref="Toplevel"/> views.
     /// </summary>
     /// <param name="top">The Toplevel to adjust.</param>
-    public virtual void PositionToplevel (Toplevel top)
+    public virtual void PositionToplevel (Toplevel? top)
     {
-        View superView = GetLocationEnsuringFullVisibility (
+        if (top is null)
+        {
+            return;
+        }
+
+        View? superView = GetLocationEnsuringFullVisibility (
                                                             top,
                                                             top.Frame.X,
                                                             top.Frame.Y,
                                                             out int nx,
                                                             out int ny,
-                                                            out StatusBar sb
+                                                            out StatusBar? sb
                                                            );
 
         if (superView is null)
@@ -482,25 +491,25 @@ public partial class Toplevel : View
             maxWidth -= superView.GetAdornmentsThickness ().Left + superView.GetAdornmentsThickness ().Right;
         }
 
-        if ((superView != top || top?.SuperView is { } || (top != Application.Top && top.Modal) || (top?.SuperView is null && top.IsOverlapped))
-            && (top.Frame.X + top.Frame.Width > maxWidth || ny > top.Frame.Y))
+        if ((superView != top || top?.SuperView is { } || (top != Application.Top && top!.Modal) || (top?.SuperView is null && ApplicationOverlapped.IsOverlapped (top)))
+            && (top!.Frame.X + top.Frame.Width > maxWidth || ny > top.Frame.Y))
         {
-            if ((top.X is null || top.X is PosAbsolute) && top.Frame.X != nx)
+            if (top?.X is null or PosAbsolute && top?.Frame.X != nx)
             {
-                top.X = nx;
+                top!.X = nx;
                 layoutSubviews = true;
             }
 
-            if ((top.Y is null || top.Y is PosAbsolute) && top.Frame.Y != ny)
+            if (top?.Y is null or PosAbsolute && top?.Frame.Y != ny)
             {
-                top.Y = ny;
+                top!.Y = ny;
                 layoutSubviews = true;
             }
         }
 
         // TODO: v2 - This is a hack to get the StatusBar to be positioned correctly.
         if (sb != null
-            && !top.Subviews.Contains (sb)
+            && !top!.Subviews.Contains (sb)
             && ny + top.Frame.Height != superView.Frame.Height - (sb.Visible ? 1 : 0)
             && top.Height is DimFill
             && -top.Height.GetAnchor (0) < 1)
@@ -521,7 +530,7 @@ public partial class Toplevel : View
     }
 
     /// <summary>Invoked when the terminal has been resized. The new <see cref="Size"/> of the terminal is provided.</summary>
-    public event EventHandler<SizeChangedEventArgs> SizeChanging;
+    public event EventHandler<SizeChangedEventArgs>? SizeChanging;
 
     private bool OutsideTopFrame (Toplevel top)
     {
@@ -560,7 +569,7 @@ public class ToplevelEqualityComparer : IEqualityComparer<Toplevel>
     /// <param name="x">The first object of type <see cref="Toplevel"/> to compare.</param>
     /// <param name="y">The second object of type <see cref="Toplevel"/> to compare.</param>
     /// <returns><see langword="true"/> if the specified objects are equal; otherwise, <see langword="false"/>.</returns>
-    public bool Equals (Toplevel x, Toplevel y)
+    public bool Equals (Toplevel? x, Toplevel? y)
     {
         if (y is null && x is null)
         {
@@ -623,7 +632,7 @@ public sealed class ToplevelComparer : IComparer<Toplevel>
     ///     <paramref name="x"/> equals <paramref name="y"/> .Greater than zero <paramref name="x"/> is greater than
     ///     <paramref name="y"/>.
     /// </returns>
-    public int Compare (Toplevel x, Toplevel y)
+    public int Compare (Toplevel? x, Toplevel? y)
     {
         if (ReferenceEquals (x, y))
         {
@@ -640,6 +649,6 @@ public sealed class ToplevelComparer : IComparer<Toplevel>
             return 1;
         }
 
-        return string.Compare (x.Id, y.Id);
+        return string.CompareOrdinal (x.Id, y.Id);
     }
 }
diff --git a/Terminal.Gui/Views/ToplevelOverlapped.cs b/Terminal.Gui/Views/ToplevelOverlapped.cs
index 06dac3694..28513c4ce 100644
--- a/Terminal.Gui/Views/ToplevelOverlapped.cs
+++ b/Terminal.Gui/Views/ToplevelOverlapped.cs
@@ -2,9 +2,6 @@
 
 public partial class Toplevel
 {
-    /// <summary>Gets or sets if this Toplevel is in overlapped mode within a Toplevel container.</summary>
-    public bool IsOverlapped => ApplicationOverlapped.OverlappedTop is { } && ApplicationOverlapped.OverlappedTop != this && !Modal;
-
     /// <summary>Gets or sets if this Toplevel is a container for overlapped children.</summary>
     public bool IsOverlappedContainer { get; set; }
 }
diff --git a/UICatalog/UICatalog.cs b/UICatalog/UICatalog.cs
index a9014d017..86352717a 100644
--- a/UICatalog/UICatalog.cs
+++ b/UICatalog/UICatalog.cs
@@ -658,7 +658,7 @@ internal class UICatalogApp
 
             ColorScheme = Colors.ColorSchemes [_topLevelColorScheme];
 
-            MenuBar.Menus [0].Children [0].Shortcut = (KeyCode)Application.QuitKey;
+            MenuBar!.Menus [0].Children [0].Shortcut = (KeyCode)Application.QuitKey;
 
             if (StatusBar is { })
             {
@@ -942,7 +942,7 @@ internal class UICatalogApp
                                              {
                                                  MiIsMenuBorderDisabled.Checked = (bool)!MiIsMenuBorderDisabled.Checked!;
 
-                                                 MenuBar.MenusBorderStyle = !(bool)MiIsMenuBorderDisabled.Checked
+                                                 MenuBar!.MenusBorderStyle = !(bool)MiIsMenuBorderDisabled.Checked
                                                                                 ? LineStyle.Single
                                                                                 : LineStyle.None;
                                              };
@@ -985,7 +985,7 @@ internal class UICatalogApp
             MiUseSubMenusSingleFrame.Action += () =>
                                                {
                                                    MiUseSubMenusSingleFrame.Checked = (bool)!MiUseSubMenusSingleFrame.Checked!;
-                                                   MenuBar.UseSubMenusSingleFrame = (bool)MiUseSubMenusSingleFrame.Checked;
+                                                   MenuBar!.UseSubMenusSingleFrame = (bool)MiUseSubMenusSingleFrame.Checked;
                                                };
             menuItems.Add (MiUseSubMenusSingleFrame);
 
diff --git a/UnitTests/Views/OverlappedTests.cs b/UnitTests/Views/OverlappedTests.cs
index 91555ca91..80c8e18c2 100644
--- a/UnitTests/Views/OverlappedTests.cs
+++ b/UnitTests/Views/OverlappedTests.cs
@@ -231,11 +231,11 @@ public class OverlappedTests
 
         Application.Iteration += (s, a) =>
                                  {
-                                     Assert.False (overlapped.IsOverlapped);
-                                     Assert.True (c1.IsOverlapped);
-                                     Assert.True (c2.IsOverlapped);
-                                     Assert.True (c3.IsOverlapped);
-                                     Assert.False (d.IsOverlapped);
+                                     Assert.False (ApplicationOverlapped.IsOverlapped(overlapped));
+                                     Assert.True (ApplicationOverlapped.IsOverlapped(c1));
+                                     Assert.True (ApplicationOverlapped.IsOverlapped(c2));
+                                     Assert.True (ApplicationOverlapped.IsOverlapped(c3));
+                                     Assert.False (ApplicationOverlapped.IsOverlapped(d));
 
                                      overlapped.RequestStop ();
                                  };
@@ -1068,11 +1068,11 @@ public class OverlappedTests
         Assert.False (top.IsCurrentTop);
         Assert.Equal (win1, Application.Current);
         Assert.True (win1.IsCurrentTop);
-        Assert.True (win1.IsOverlapped);
+        Assert.True (ApplicationOverlapped.IsOverlapped(win1));
         Assert.Null (top.Focused);
         Assert.Null (top.MostFocused);
         Assert.Equal (tf1W1, win1.MostFocused);
-        Assert.True (win1.IsOverlapped);
+        Assert.True (ApplicationOverlapped.IsOverlapped(win1));
         Assert.Single (ApplicationOverlapped.OverlappedChildren!);
         Application.Begin (win2);
         Assert.Equal (new (0, 0, 40, 25), win2.Frame);
@@ -1080,7 +1080,7 @@ public class OverlappedTests
         Assert.False (top.IsCurrentTop);
         Assert.Equal (win2, Application.Current);
         Assert.True (win2.IsCurrentTop);
-        Assert.True (win2.IsOverlapped);
+        Assert.True (ApplicationOverlapped.IsOverlapped(win2));
         Assert.Null (top.Focused);
         Assert.Null (top.MostFocused);
         Assert.Equal (tf1W2, win2.MostFocused);
diff --git a/UnitTests/Views/ToplevelTests.cs b/UnitTests/Views/ToplevelTests.cs
index 8688c5d4a..9af790add 100644
--- a/UnitTests/Views/ToplevelTests.cs
+++ b/UnitTests/Views/ToplevelTests.cs
@@ -17,7 +17,7 @@ public partial class ToplevelTests (ITestOutputHelper output)
         Assert.Null (top.MenuBar);
         Assert.Null (top.StatusBar);
         Assert.False (top.IsOverlappedContainer);
-        Assert.False (top.IsOverlapped);
+        Assert.False (ApplicationOverlapped.IsOverlapped(top));
     }
 
     [Fact]

From ca4d10b5093dc406f1b07c648e27f17086b2cee0 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Wed, 24 Jul 2024 19:22:59 -0600
Subject: [PATCH 28/33] WIP: Modify Focus logic to properly deal with
 ViewArrangement.Overlapped.

---
 Terminal.Gui/View/Adornment/Border.cs  |   9 +-
 Terminal.Gui/View/ViewArrangement.cs   |  13 +-
 Terminal.Gui/View/ViewSubViews.cs      |  62 ++++--
 UICatalog/Scenarios/ViewExperiments.cs | 249 ++++++-------------------
 4 files changed, 128 insertions(+), 205 deletions(-)

diff --git a/Terminal.Gui/View/Adornment/Border.cs b/Terminal.Gui/View/Adornment/Border.cs
index 41fd02f9d..241b795c5 100644
--- a/Terminal.Gui/View/Adornment/Border.cs
+++ b/Terminal.Gui/View/Adornment/Border.cs
@@ -279,10 +279,11 @@ public class Border : Adornment
             return true;
         }
 
-        if (!Parent.CanFocus)
-        {
-            return false;
-        }
+        // BUGBUG: Shouldn't non-focusable views be draggable??
+        //if (!Parent.CanFocus)
+        //{
+        //    return false;
+        //}
 
         if (!Parent.Arrangement.HasFlag (ViewArrangement.Movable))
         {
diff --git a/Terminal.Gui/View/ViewArrangement.cs b/Terminal.Gui/View/ViewArrangement.cs
index b24529caf..df13c4762 100644
--- a/Terminal.Gui/View/ViewArrangement.cs
+++ b/Terminal.Gui/View/ViewArrangement.cs
@@ -53,7 +53,18 @@ public enum ViewArrangement
     /// <remarks>
     ///     If <see cref="Movable"/> is also set, the top will not be resizable.
     /// </remarks>
-    Resizable = LeftResizable | RightResizable | TopResizable | BottomResizable
+    Resizable = LeftResizable | RightResizable | TopResizable | BottomResizable,
+
+    /// <summary>
+    ///    The view overlap other views.
+    /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         When set, Tab and Shift-Tab will be constrained to the subviews of the view (normally, they will navigate to the next/prev view in the next/prev Tabindex).
+    ///         Use Ctrl-Tab (Ctrl-PageDown) / Ctrl-Shift-Tab (Ctrl-PageUp) to move between overlapped views.
+    ///     </para>
+    /// </remarks>
+    Overlapped = 32
 }
 public partial class View
 {
diff --git a/Terminal.Gui/View/ViewSubViews.cs b/Terminal.Gui/View/ViewSubViews.cs
index 5da8dd76a..79cca431e 100644
--- a/Terminal.Gui/View/ViewSubViews.cs
+++ b/Terminal.Gui/View/ViewSubViews.cs
@@ -672,7 +672,7 @@ public partial class View
     /// <summary>
     ///     Focuses the last focusable view in <see cref="View.TabIndexes"/> if one exists. If there are no views in <see cref="View.TabIndexes"/> then the focus is set to the view itself.
     /// </summary>
-    public void FocusFirst ()
+    public void FocusFirst (bool overlapped = false)
     {
         if (!CanBeVisible (this))
         {
@@ -686,7 +686,7 @@ public partial class View
             return;
         }
 
-        foreach (View view in _tabIndexes)
+        foreach (View view in _tabIndexes.Where (v => !overlapped || v.Arrangement.HasFlag (ViewArrangement.Overlapped)))
         {
             if (view.CanFocus && view._tabStop && view.Visible && view.Enabled)
             {
@@ -700,7 +700,7 @@ public partial class View
     /// <summary>
     ///     Focuses the last focusable view in <see cref="View.TabIndexes"/> if one exists. If there are no views in <see cref="View.TabIndexes"/> then the focus is set to the view itself.
     /// </summary>
-    public void FocusLast ()
+    public void FocusLast (bool overlapped = false)
     {
         if (!CanBeVisible (this))
         {
@@ -714,15 +714,11 @@ public partial class View
             return;
         }
 
-        for (int i = _tabIndexes.Count; i > 0;)
+        foreach (View view in _tabIndexes.Where (v => !overlapped || v.Arrangement.HasFlag (ViewArrangement.Overlapped)).Reverse ())
         {
-            i--;
-
-            View v = _tabIndexes [i];
-
-            if (v.CanFocus && v._tabStop && v.Visible && v.Enabled)
+            if (view.CanFocus && view._tabStop && view.Visible && view.Enabled)
             {
-                SetFocus (v);
+                SetFocus (view);
 
                 return;
             }
@@ -777,6 +773,18 @@ public partial class View
             {
                 Focused.SetHasFocus (false, w);
 
+                // If the focused view is overlapped don't focus on the next if it's not overlapped.
+                if (Focused.Arrangement.HasFlag (ViewArrangement.Overlapped) && !w.Arrangement.HasFlag (ViewArrangement.Overlapped))
+                {
+                    return false;
+                }
+
+                // If the focused view is not overlapped and the next is, skip it
+                if (!Focused.Arrangement.HasFlag (ViewArrangement.Overlapped) && w.Arrangement.HasFlag (ViewArrangement.Overlapped))
+                {
+                   continue;
+                }
+
                 if (w.CanFocus && w._tabStop && w.Visible && w.Enabled)
                 {
                     w.FocusLast ();
@@ -788,9 +796,19 @@ public partial class View
             }
         }
 
+        // There's no prev view in tab indexes.
         if (Focused is { })
         {
+            // Leave Focused
             Focused.SetHasFocus (false, this);
+
+            if (Focused.Arrangement.HasFlag (ViewArrangement.Overlapped))
+            {
+                FocusLast (true);
+                return true;
+            }
+
+            // Signal to caller no next view was found
             Focused = null;
         }
 
@@ -798,7 +816,7 @@ public partial class View
     }
 
     /// <summary>
-    ///     Focuses the previous view in <see cref="View.TabIndexes"/>. If there is no previous view, the focus is set to the view itself.
+    ///     Focuses the next view in <see cref="View.TabIndexes"/>. If there is no next view, the focus is set to the view itself.
     /// </summary>
     /// <returns><see langword="true"/> if next was focused, <see langword="false"/> otherwise.</returns>
     public bool FocusNext ()
@@ -844,6 +862,18 @@ public partial class View
             {
                 Focused.SetHasFocus (false, w);
 
+                // If the focused view is overlapped don't focus on the next if it's not overlapped.
+                if (Focused.Arrangement.HasFlag (ViewArrangement.Overlapped) && !w.Arrangement.HasFlag (ViewArrangement.Overlapped))
+                {
+                    return false;
+                }
+
+                // If the focused view is not overlapped and the next is, skip it
+                if (!Focused.Arrangement.HasFlag (ViewArrangement.Overlapped) && w.Arrangement.HasFlag (ViewArrangement.Overlapped))
+                {
+                    continue;
+                }
+
                 if (w.CanFocus && w._tabStop && w.Visible && w.Enabled)
                 {
                     w.FocusFirst ();
@@ -855,9 +885,19 @@ public partial class View
             }
         }
 
+        // There's no next view in tab indexes.
         if (Focused is { })
         {
+            // Leave Focused
             Focused.SetHasFocus (false, this);
+
+            if (Focused.Arrangement.HasFlag (ViewArrangement.Overlapped))
+            {
+                FocusFirst (true);
+                return true;
+            }
+
+            // Signal to caller no next view was found
             Focused = null;
         }
 
diff --git a/UICatalog/Scenarios/ViewExperiments.cs b/UICatalog/Scenarios/ViewExperiments.cs
index 5d08f0aa6..263a507d9 100644
--- a/UICatalog/Scenarios/ViewExperiments.cs
+++ b/UICatalog/Scenarios/ViewExperiments.cs
@@ -18,233 +18,104 @@ public class ViewExperiments : Scenario
             Title = GetQuitKeyAndName ()
         };
 
-        var containerLabel = new Label
-        {
-            X = 0,
-            Y = 0,
-
-            Width = Dim.Fill (),
-            Height = 3
-        };
-        app.Add (containerLabel);
-
         var view = new View
         {
             X = 2,
-            Y = Pos.Bottom (containerLabel),
-            Height = Dim.Fill (2),
-            Width = Dim.Fill (2),
-            Title = "View with 2xMargin, 2xBorder, & 2xPadding",
+            Y = 2,
+            Height = Dim.Auto (),
+            Width = Dim.Auto (),
+            Title = "View1",
             ColorScheme = Colors.ColorSchemes ["Base"],
-            Id = "DaView"
+            Id = "View1",
+            CanFocus = true, // Can't drag without this? BUGBUG
+            Arrangement = ViewArrangement.Movable | ViewArrangement.Overlapped
         };
 
+        Button button = new ()
+        {
+            Title = "Button_1",
+        };
+        view.Add (button);
+
+        button = new ()
+        {
+            Y = Pos.Bottom (button),
+            Title = "Button_2",
+        };
+        view.Add (button);
+
         //app.Add (view);
 
-        view.Margin.Thickness = new (2, 2, 2, 2);
+        view.Margin.Thickness = new (0);
         view.Margin.ColorScheme = Colors.ColorSchemes ["Toplevel"];
         view.Margin.Data = "Margin";
-        view.Border.Thickness = new (3);
-        view.Border.LineStyle = LineStyle.Single;
+        view.Border.Thickness = new (1);
+        view.Border.LineStyle = LineStyle.Double;
         view.Border.ColorScheme = view.ColorScheme;
         view.Border.Data = "Border";
-        view.Padding.Thickness = new (2);
+        view.Padding.Thickness = new (0);
         view.Padding.ColorScheme = Colors.ColorSchemes ["Error"];
         view.Padding.Data = "Padding";
 
-        var window1 = new Window
+        var view2 = new View
         {
-            X = 2,
-            Y = 3,
-            Height = 7,
-            Width = 17,
-            Title = "Window 1",
-            Text = "Window #2",
-            TextAlignment = Alignment.Center
+            X = Pos.Right (view),
+            Y = Pos.Bottom (view),
+            Height = Dim.Auto (),
+            Width = Dim.Auto (),
+            Title = "View2",
+            ColorScheme = Colors.ColorSchemes ["Base"],
+            Id = "View2",
+            CanFocus = true, // Can't drag without this? BUGBUG
+            Arrangement = ViewArrangement.Movable | ViewArrangement.Overlapped
         };
 
-        window1.Margin.Thickness = new (0);
-        window1.Margin.ColorScheme = Colors.ColorSchemes ["Toplevel"];
-        window1.Margin.Data = "Margin";
-        window1.Border.Thickness = new (1);
-        window1.Border.LineStyle = LineStyle.Single;
-        window1.Border.ColorScheme = view.ColorScheme;
-        window1.Border.Data = "Border";
-        window1.Padding.Thickness = new (0);
-        window1.Padding.ColorScheme = Colors.ColorSchemes ["Error"];
-        window1.Padding.Data = "Padding";
 
-        view.Add (window1);
-
-        var window2 = new Window
+        button = new ()
         {
-            X = Pos.Right (window1) + 1,
-            Y = 3,
-            Height = 5,
-            Width = 37,
-            Title = "Window2",
-            Text = "Window #2 (Right(window1)+1",
-            TextAlignment = Alignment.Center
+            Title = "Button_3",
         };
+        view2.Add (button);
 
-        //view3.InitializeFrames ();
-        window2.Margin.Thickness = new (1, 1, 0, 0);
-        window2.Margin.ColorScheme = Colors.ColorSchemes ["Toplevel"];
-        window2.Margin.Data = "Margin";
-        window2.Border.Thickness = new (1, 1, 1, 1);
-        window2.Border.LineStyle = LineStyle.Single;
-        window2.Border.ColorScheme = view.ColorScheme;
-        window2.Border.Data = "Border";
-        window2.Padding.Thickness = new (1, 1, 0, 0);
-        window2.Padding.ColorScheme = Colors.ColorSchemes ["Error"];
-        window2.Padding.Data = "Padding";
-
-        view.Add (window2);
-
-        var view4 = new View
+        button = new ()
         {
-            X = Pos.Right (window2) + 1,
-            Y = 3,
-            Height = 5,
-            Width = 37,
-            Title = "View4",
-            Text = "View #4 (Right(window2)+1",
-            TextAlignment = Alignment.Center
+            Y = Pos.Bottom (button),
+            Title = "Button_4",
         };
+        view2.Add (button);
 
-        //view4.InitializeFrames ();
-        view4.Margin.Thickness = new (0, 0, 1, 1);
-        view4.Margin.ColorScheme = Colors.ColorSchemes ["Toplevel"];
-        view4.Margin.Data = "Margin";
-        view4.Border.Thickness = new (1, 1, 1, 1);
-        view4.Border.LineStyle = LineStyle.Single;
-        view4.Border.ColorScheme = view.ColorScheme;
-        view4.Border.Data = "Border";
-        view4.Padding.Thickness = new (0, 0, 1, 1);
-        view4.Padding.ColorScheme = Colors.ColorSchemes ["Error"];
-        view4.Padding.Data = "Padding";
+        view2.Add (button);
+        view2.Margin.Thickness = new (0);
+        view2.Margin.ColorScheme = Colors.ColorSchemes ["Toplevel"];
+        view2.Margin.Data = "Margin";
+        view2.Border.Thickness = new (1);
+        view2.Border.LineStyle = LineStyle.Double;
+        view2.Border.ColorScheme = view2.ColorScheme;
+        view2.Border.Data = "Border";
+        view2.Padding.Thickness = new (0);
+        view2.Padding.ColorScheme = Colors.ColorSchemes ["Error"];
+        view2.Padding.Data = "Padding";
 
-        view.Add (view4);
-
-        var view5 = new View
+        button = new ()
         {
-            X = Pos.Right (view4) + 1,
-            Y = 3,
-            Height = Dim.Fill (2),
-            Width = Dim.Fill (),
-            Title = "View5",
-            Text = "View #5 (Right(view4)+1 Fill",
-            TextAlignment = Alignment.Center
+            X = Pos.AnchorEnd (),
+            Y = Pos.AnchorEnd (),
+            Title = "Button_5",
         };
 
-        //view5.InitializeFrames ();
-        view5.Margin.Thickness = new (0, 0, 0, 0);
-        view5.Margin.ColorScheme = Colors.ColorSchemes ["Toplevel"];
-        view5.Margin.Data = "Margin";
-        view5.Border.Thickness = new (1, 1, 1, 1);
-        view5.Border.LineStyle = LineStyle.Single;
-        view5.Border.ColorScheme = view.ColorScheme;
-        view5.Border.Data = "Border";
-        view5.Padding.Thickness = new (0, 0, 0, 0);
-        view5.Padding.ColorScheme = Colors.ColorSchemes ["Error"];
-        view5.Padding.Data = "Padding";
-
-        view.Add (view5);
-
-        var label = new Label { Text = "AutoSize true; 1;1:", X = 1, Y = 1 };
-        view.Add (label);
-
-        var edit = new TextField
-        {
-            Text = "Right (label)",
-            X = Pos.Right (label),
-            Y = 1,
-            Width = 15,
-            Height = 1
-        };
-        view.Add (edit);
-
-        edit = new()
-        {
-            Text = "Right (edit) + 1",
-            X = Pos.Right (edit) + 1,
-            Y = 1,
-            Width = 20,
-            Height = 1
-        };
-        view.Add (edit);
-
-        var label50 = new View
-        {
-            Title = "Border Inherit Demo",
-            Text = "Center();50%",
-            X = Pos.Center (),
-            Y = Pos.Percent (50),
-            Width = 30,
-            TextAlignment = Alignment.Center
-        };
-        label50.Border.Thickness = new (1, 3, 1, 1);
-        label50.Height = 5;
-        view.Add (label50);
-
-        edit = new()
-        {
-            Text = "0 + Percent(50);70%",
-            X = 0 + Pos.Percent (50),
-            Y = Pos.Percent (70),
-            Width = 30,
-            Height = 1
-        };
-        view.Add (edit);
-
-        edit = new() { Text = "AnchorEnd ();AnchorEnd ()", X = Pos.AnchorEnd (), Y = Pos.AnchorEnd (), Width = 30, Height = 1 };
-        view.Add (edit);
-
-        edit = new()
-        {
-            Text = "Left;AnchorEnd (2)",
-            X = 0,
-            Y = Pos.AnchorEnd (2),
-            Width = 30,
-            Height = 1
-        };
-        view.Add (edit);
-
-        view.LayoutComplete += (s, e) =>
-                               {
-                                   containerLabel.Text =
-                                       $"Container.Frame: {
-                                           app.Frame
-                                       } .Bounds: {
-                                           app.Viewport
-                                       }\nView.Frame: {
-                                           view.Frame
-                                       } .Viewport: {
-                                           view.Viewport
-                                       } .viewportOffset: {
-                                           view.GetViewportOffsetFromFrame ()
-                                       }\n .Padding.Frame: {
-                                           view.Padding.Frame
-                                       } .Padding.Viewport: {
-                                           view.Padding.Viewport
-                                       }";
-                               };
-
-        view.X = Pos.Center ();
-
         var editor = new AdornmentsEditor
         {
             X = 0,
-            Y = Pos.Bottom (containerLabel),
+            Y = 0,
             AutoSelectViewToEdit = true
         };
 
         app.Add (editor);
-        view.X = 36;
+        view.X = 34;
         view.Y = 4;
-        view.Width = Dim.Fill ();
-        view.Height = Dim.Fill ();
         app.Add (view);
+        app.Add (view2);
+        app.Add (button);
 
         Application.Run (app);
         app.Dispose ();

From 3a40851848ef741076f80a5de2dafcabdbf57d37 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Wed, 24 Jul 2024 19:45:25 -0600
Subject: [PATCH 29/33] WIP: More - Modify Focus logic to properly deal with
 ViewArrangement.Overlapped.

---
 .../Application/Application.Navigation.cs     | 39 ++++++++++++++++---
 1 file changed, 34 insertions(+), 5 deletions(-)

diff --git a/Terminal.Gui/Application/Application.Navigation.cs b/Terminal.Gui/Application/Application.Navigation.cs
index fde03913b..6f80320b8 100644
--- a/Terminal.Gui/Application/Application.Navigation.cs
+++ b/Terminal.Gui/Application/Application.Navigation.cs
@@ -1,4 +1,6 @@
 #nullable enable
+using System.Security.Cryptography;
+
 namespace Terminal.Gui;
 
 /// <summary>
@@ -78,8 +80,10 @@ internal static class ApplicationNavigation
             idx++;
         }
     }
+
     /// <summary>
-    ///     Moves the focus to 
+    ///     Moves the focus to the next view. Honors <see cref="ViewArrangement.Overlapped"/> and will only move to the next subview
+    ///     if the current and next subviews are not overlapped.
     /// </summary>
     internal static void MoveNextView ()
     {
@@ -101,19 +105,40 @@ internal static class ApplicationNavigation
         }
     }
 
+    /// <summary>
+    ///     Moves the focus to the next <see cref="Toplevel"/> subview or the next subview that has <see cref="ApplicationOverlapped.OverlappedTop"/> set.
+    /// </summary>
     internal static void MoveNextViewOrTop ()
     {
         if (ApplicationOverlapped.OverlappedTop is null)
         {
             Toplevel? top = Application.Current!.Modal ? Application.Current : Application.Top;
-            top!.FocusNext ();
 
-            if (top.Focused is null)
+            if (!Application.Current.FocusNext ())
             {
-                top.FocusNext ();
+                Application.Current.FocusNext ();
             }
 
-            top.SetNeedsDisplay ();
+            if (top != Application.Current.Focused && top != Application.Current.Focused?.Focused)
+            {
+                top?.SetNeedsDisplay ();
+                Application.Current.Focused?.SetNeedsDisplay ();
+            }
+            else
+            {
+                FocusNearestView (Application.Current.SuperView?.TabIndexes, View.NavigationDirection.Forward);
+            }
+
+
+
+            //top!.FocusNext ();
+
+            //if (top.Focused is null)
+            //{
+            //    top.FocusNext ();
+            //}
+
+            //top.SetNeedsDisplay ();
             ApplicationOverlapped.BringOverlappedTopToFront ();
         }
         else
@@ -122,6 +147,10 @@ internal static class ApplicationNavigation
         }
     }
 
+    /// <summary>
+    ///     Moves the focus to the next view. Honors <see cref="ViewArrangement.Overlapped"/> and will only move to the next subview
+    ///     if the current and next subviews are not overlapped.
+    /// </summary>
     internal static void MovePreviousView ()
     {
         View? old = GetDeepestFocusedSubview (Application.Current!.Focused);

From d874f5628295f2811f59ba1321be11f5bb385af5 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Thu, 25 Jul 2024 10:40:28 -0600
Subject: [PATCH 30/33] Reorganized View source files to get my head straight

---
 .../Application/Application.Keyboard.cs       |  30 +-
 Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs  |  42 -
 .../ConsoleDrivers/CursorVisibility.cs        |  44 +
 Terminal.Gui/View/DrawEventArgs.cs            |  29 +
 Terminal.Gui/View/Layout/LayoutEventArgs.cs   |  12 +
 .../View/Navigation/FocusEventArgs.cs         |  27 +
 .../{ViewAdornments.cs => View.Adornments.cs} |   2 +-
 Terminal.Gui/View/View.Arrangement.cs         |  15 +
 .../View/{ViewContent.cs => View.Content.cs}  |   0
 Terminal.Gui/View/View.Cursor.cs              |  35 +
 ...ViewDiagnostics.cs => View.Diagnostics.cs} |   0
 .../View/{ViewDrawing.cs => View.Drawing.cs}  |   2 +-
 Terminal.Gui/View/View.Hierarchy.cs           | 320 ++++++
 .../{ViewKeyboard.cs => View.Keyboard.cs}     | 115 +--
 .../{Layout/ViewLayout.cs => View.Layout.cs}  |   2 +-
 .../View/{ViewMouse.cs => View.Mouse.cs}      |   2 +-
 Terminal.Gui/View/View.Navigation.cs          | 813 +++++++++++++++
 .../View/{ViewText.cs => View.Text.cs}        |   2 +-
 Terminal.Gui/View/ViewArrangement.cs          |  30 +-
 Terminal.Gui/View/ViewEventArgs.cs            |  67 +-
 Terminal.Gui/View/ViewSubViews.cs             | 948 ------------------
 UICatalog/Scenarios/ViewExperiments.cs        |  25 +-
 22 files changed, 1318 insertions(+), 1244 deletions(-)
 create mode 100644 Terminal.Gui/ConsoleDrivers/CursorVisibility.cs
 create mode 100644 Terminal.Gui/View/DrawEventArgs.cs
 create mode 100644 Terminal.Gui/View/Layout/LayoutEventArgs.cs
 create mode 100644 Terminal.Gui/View/Navigation/FocusEventArgs.cs
 rename Terminal.Gui/View/{ViewAdornments.cs => View.Adornments.cs} (99%)
 create mode 100644 Terminal.Gui/View/View.Arrangement.cs
 rename Terminal.Gui/View/{ViewContent.cs => View.Content.cs} (100%)
 create mode 100644 Terminal.Gui/View/View.Cursor.cs
 rename Terminal.Gui/View/{ViewDiagnostics.cs => View.Diagnostics.cs} (100%)
 rename Terminal.Gui/View/{ViewDrawing.cs => View.Drawing.cs} (99%)
 create mode 100644 Terminal.Gui/View/View.Hierarchy.cs
 rename Terminal.Gui/View/{ViewKeyboard.cs => View.Keyboard.cs} (91%)
 rename Terminal.Gui/View/{Layout/ViewLayout.cs => View.Layout.cs} (99%)
 rename Terminal.Gui/View/{ViewMouse.cs => View.Mouse.cs} (99%)
 create mode 100644 Terminal.Gui/View/View.Navigation.cs
 rename Terminal.Gui/View/{ViewText.cs => View.Text.cs} (99%)
 delete mode 100644 Terminal.Gui/View/ViewSubViews.cs

diff --git a/Terminal.Gui/Application/Application.Keyboard.cs b/Terminal.Gui/Application/Application.Keyboard.cs
index d26dcd432..969d4c31e 100644
--- a/Terminal.Gui/Application/Application.Keyboard.cs
+++ b/Terminal.Gui/Application/Application.Keyboard.cs
@@ -267,34 +267,6 @@ public static partial class Application // Keyboard handling
         CommandImplementations [command] = ctx => f ();
     }
 
-    ///// <summary>
-    /////     The <see cref="KeyBindingScope.Application"/> key bindings.
-    ///// </summary>
-    //private static readonly Dictionary<Key, List<View?>> _keyBindings = new ();
-
-    ///// <summary>
-    ///// Gets the list of <see cref="KeyBindingScope.Application"/> key bindings.
-    ///// </summary>
-    //public static Dictionary<Key, List<View?>> GetKeyBindings () { return _keyBindings; }
-
-    ///// <summary>
-    /////     Adds an  <see cref="KeyBindingScope.Application"/> scoped key binding.
-    ///// </summary>
-    ///// <remarks>
-    /////     This is an internal method used by the <see cref="View"/> class to add Application key bindings.
-    ///// </remarks>
-    ///// <param name="key">The key being bound.</param>
-    ///// <param name="view">The view that is bound to the key. If <see langword="null"/>, <see cref="Application.Current"/> will be used.</param>
-    //internal static void AddKeyBinding (Key key, View? view)
-    //{
-    //    if (!_keyBindings.ContainsKey (key))
-    //    {
-    //        _keyBindings [key] = [];
-    //    }
-
-    //    _keyBindings [key].Add (view);
-    //}
-
     internal static void AddApplicationKeyBindings ()
     {
         // Things this view knows how to do
@@ -326,7 +298,7 @@ public static partial class Application // Keyboard handling
                    );
 
         AddCommand (
-                    Command.NextView,    
+                    Command.NextView,
                     () =>
                     {
                         // TODO: Move this method to Application.Navigation.cs
diff --git a/Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs b/Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs
index e99521d1e..dc5c785a0 100644
--- a/Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs
+++ b/Terminal.Gui/ConsoleDrivers/ConsoleDriver.cs
@@ -603,48 +603,6 @@ public abstract class ConsoleDriver
     #endregion
 }
 
-/// <summary>Terminal Cursor Visibility settings.</summary>
-/// <remarks>
-///     Hex value are set as 0xAABBCCDD where : AA stand for the TERMINFO DECSUSR parameter value to be used under
-///     Linux and MacOS BB stand for the NCurses curs_set parameter value to be used under Linux and MacOS CC stand for the
-///     CONSOLE_CURSOR_INFO.bVisible parameter value to be used under Windows DD stand for the CONSOLE_CURSOR_INFO.dwSize
-///     parameter value to be used under Windows
-/// </remarks>
-public enum CursorVisibility
-{
-    /// <summary>Cursor caret has default</summary>
-    /// <remarks>
-    ///     Works under Xterm-like terminal otherwise this is equivalent to <see ref="Underscore"/>. This default directly
-    ///     depends on the XTerm user configuration settings, so it could be Block, I-Beam, Underline with possible blinking.
-    /// </remarks>
-    Default = 0x00010119,
-
-    /// <summary>Cursor caret is hidden</summary>
-    Invisible = 0x03000019,
-
-    /// <summary>Cursor caret is normally shown as a blinking underline bar _</summary>
-    Underline = 0x03010119,
-
-    /// <summary>Cursor caret is normally shown as a underline bar _</summary>
-    /// <remarks>Under Windows, this is equivalent to <see ref="UnderscoreBlinking"/></remarks>
-    UnderlineFix = 0x04010119,
-
-    /// <summary>Cursor caret is displayed a blinking vertical bar |</summary>
-    /// <remarks>Works under Xterm-like terminal otherwise this is equivalent to <see ref="Underscore"/></remarks>
-    Vertical = 0x05010119,
-
-    /// <summary>Cursor caret is displayed a blinking vertical bar |</summary>
-    /// <remarks>Works under Xterm-like terminal otherwise this is equivalent to <see ref="Underscore"/></remarks>
-    VerticalFix = 0x06010119,
-
-    /// <summary>Cursor caret is displayed as a blinking block ▉</summary>
-    Box = 0x01020164,
-
-    /// <summary>Cursor caret is displayed a block ▉</summary>
-    /// <remarks>Works under Xterm-like terminal otherwise this is equivalent to <see ref="Block"/></remarks>
-    BoxFix = 0x02020164
-}
-
 /// <summary>
 ///     The <see cref="KeyCode"/> enumeration encodes key information from <see cref="ConsoleDriver"/>s and provides a
 ///     consistent way for application code to specify keys and receive key events.
diff --git a/Terminal.Gui/ConsoleDrivers/CursorVisibility.cs b/Terminal.Gui/ConsoleDrivers/CursorVisibility.cs
new file mode 100644
index 000000000..b96d31fd4
--- /dev/null
+++ b/Terminal.Gui/ConsoleDrivers/CursorVisibility.cs
@@ -0,0 +1,44 @@
+#nullable enable
+namespace Terminal.Gui;
+
+/// <summary>Terminal Cursor Visibility settings.</summary>
+/// <remarks>
+///     Hex value are set as 0xAABBCCDD where : AA stand for the TERMINFO DECSUSR parameter value to be used under
+///     Linux and MacOS BB stand for the NCurses curs_set parameter value to be used under Linux and MacOS CC stand for the
+///     CONSOLE_CURSOR_INFO.bVisible parameter value to be used under Windows DD stand for the CONSOLE_CURSOR_INFO.dwSize
+///     parameter value to be used under Windows
+/// </remarks>
+public enum CursorVisibility
+{
+    /// <summary>Cursor caret has default</summary>
+    /// <remarks>
+    ///     Works under Xterm-like terminal otherwise this is equivalent to <see ref="Underscore"/>. This default directly
+    ///     depends on the XTerm user configuration settings, so it could be Block, I-Beam, Underline with possible blinking.
+    /// </remarks>
+    Default = 0x00010119,
+
+    /// <summary>Cursor caret is hidden</summary>
+    Invisible = 0x03000019,
+
+    /// <summary>Cursor caret is normally shown as a blinking underline bar _</summary>
+    Underline = 0x03010119,
+
+    /// <summary>Cursor caret is normally shown as a underline bar _</summary>
+    /// <remarks>Under Windows, this is equivalent to <see ref="UnderscoreBlinking"/></remarks>
+    UnderlineFix = 0x04010119,
+
+    /// <summary>Cursor caret is displayed a blinking vertical bar |</summary>
+    /// <remarks>Works under Xterm-like terminal otherwise this is equivalent to <see ref="Underscore"/></remarks>
+    Vertical = 0x05010119,
+
+    /// <summary>Cursor caret is displayed a blinking vertical bar |</summary>
+    /// <remarks>Works under Xterm-like terminal otherwise this is equivalent to <see ref="Underscore"/></remarks>
+    VerticalFix = 0x06010119,
+
+    /// <summary>Cursor caret is displayed as a blinking block ▉</summary>
+    Box = 0x01020164,
+
+    /// <summary>Cursor caret is displayed a block ▉</summary>
+    /// <remarks>Works under Xterm-like terminal otherwise this is equivalent to <see ref="Block"/></remarks>
+    BoxFix = 0x02020164
+}
diff --git a/Terminal.Gui/View/DrawEventArgs.cs b/Terminal.Gui/View/DrawEventArgs.cs
new file mode 100644
index 000000000..32c07c711
--- /dev/null
+++ b/Terminal.Gui/View/DrawEventArgs.cs
@@ -0,0 +1,29 @@
+namespace Terminal.Gui;
+
+/// <summary>Event args for draw events</summary>
+public class DrawEventArgs : EventArgs
+{
+    /// <summary>Creates a new instance of the <see cref="DrawEventArgs"/> class.</summary>
+    /// <param name="newViewport">
+    ///     The Content-relative rectangle describing the new visible viewport into the
+    ///     <see cref="View"/>.
+    /// </param>
+    /// <param name="oldViewport">
+    ///     The Content-relative rectangle describing the old visible viewport into the
+    ///     <see cref="View"/>.
+    /// </param>
+    public DrawEventArgs (Rectangle newViewport, Rectangle oldViewport)
+    {
+        NewViewport = newViewport;
+        OldViewport = oldViewport;
+    }
+
+    /// <summary>If set to true, the draw operation will be canceled, if applicable.</summary>
+    public bool Cancel { get; set; }
+
+    /// <summary>Gets the Content-relative rectangle describing the old visible viewport into the <see cref="View"/>.</summary>
+    public Rectangle OldViewport { get; }
+
+    /// <summary>Gets the Content-relative rectangle describing the currently visible viewport into the <see cref="View"/>.</summary>
+    public Rectangle NewViewport { get; }
+}
diff --git a/Terminal.Gui/View/Layout/LayoutEventArgs.cs b/Terminal.Gui/View/Layout/LayoutEventArgs.cs
new file mode 100644
index 000000000..dac959af0
--- /dev/null
+++ b/Terminal.Gui/View/Layout/LayoutEventArgs.cs
@@ -0,0 +1,12 @@
+namespace Terminal.Gui;
+
+/// <summary>Event arguments for the <see cref="View.LayoutComplete"/> event.</summary>
+public class LayoutEventArgs : EventArgs
+{
+    /// <summary>Creates a new instance of the <see cref="Terminal.Gui.LayoutEventArgs"/> class.</summary>
+    /// <param name="oldContentSize">The view that the event is about.</param>
+    public LayoutEventArgs (Size oldContentSize) { OldContentSize = oldContentSize; }
+
+    /// <summary>The viewport of the <see cref="View"/> before it was laid out.</summary>
+    public Size OldContentSize { get; set; }
+}
diff --git a/Terminal.Gui/View/Navigation/FocusEventArgs.cs b/Terminal.Gui/View/Navigation/FocusEventArgs.cs
new file mode 100644
index 000000000..6d8d28267
--- /dev/null
+++ b/Terminal.Gui/View/Navigation/FocusEventArgs.cs
@@ -0,0 +1,27 @@
+namespace Terminal.Gui;
+
+/// <summary>Defines the event arguments for <see cref="View.SetFocus()"/></summary>
+public class FocusEventArgs : EventArgs
+{
+    /// <summary>Constructs.</summary>
+    /// <param name="leaving">The view that is losing focus.</param>
+    /// <param name="entering">The view that is gaining focus.</param>
+    public FocusEventArgs (View leaving, View entering) {
+        Leaving = leaving;
+        Entering = entering;
+    }
+
+    /// <summary>
+    ///     Indicates if the current focus event has already been processed and the driver should stop notifying any other
+    ///     event subscriber. It's important to set this value to true specially when updating any View's layout from inside the
+    ///     subscriber method.
+    /// </summary>
+    public bool Handled { get; set; }
+
+    /// <summary>Indicates the view that is losing focus.</summary>
+    public View Leaving { get; set; }
+
+    /// <summary>Indicates the view that is gaining focus.</summary>
+    public View Entering { get; set; }
+
+}
diff --git a/Terminal.Gui/View/ViewAdornments.cs b/Terminal.Gui/View/View.Adornments.cs
similarity index 99%
rename from Terminal.Gui/View/ViewAdornments.cs
rename to Terminal.Gui/View/View.Adornments.cs
index accb15aba..2d179079e 100644
--- a/Terminal.Gui/View/ViewAdornments.cs
+++ b/Terminal.Gui/View/View.Adornments.cs
@@ -3,7 +3,7 @@ using System.Text.Json.Serialization;
 
 namespace Terminal.Gui;
 
-public partial class View
+public partial class View // Adornments
 {
     /// <summary>
     ///    Initializes the Adornments of the View. Called by the constructor.
diff --git a/Terminal.Gui/View/View.Arrangement.cs b/Terminal.Gui/View/View.Arrangement.cs
new file mode 100644
index 000000000..0fea93324
--- /dev/null
+++ b/Terminal.Gui/View/View.Arrangement.cs
@@ -0,0 +1,15 @@
+namespace Terminal.Gui;
+
+public partial class View
+{
+    /// <summary>
+    ///    Gets or sets the user actions that are enabled for the view within it's <see cref="SuperView"/>.
+    /// </summary>
+    /// <remarks>
+    /// <para>
+    ///     Sizing or moving a view is only possible if the <see cref="View"/> is part of a <see cref="SuperView"/> and
+    ///     the relevant position and dimensions of the <see cref="View"/> are independent of other SubViews
+    /// </para>
+    /// </remarks>
+    public ViewArrangement Arrangement { get; set; }
+}
diff --git a/Terminal.Gui/View/ViewContent.cs b/Terminal.Gui/View/View.Content.cs
similarity index 100%
rename from Terminal.Gui/View/ViewContent.cs
rename to Terminal.Gui/View/View.Content.cs
diff --git a/Terminal.Gui/View/View.Cursor.cs b/Terminal.Gui/View/View.Cursor.cs
new file mode 100644
index 000000000..bdba7d85f
--- /dev/null
+++ b/Terminal.Gui/View/View.Cursor.cs
@@ -0,0 +1,35 @@
+namespace Terminal.Gui;
+
+public partial class View
+{
+    /// <summary>
+    ///     Gets or sets the cursor style to be used when the view is focused. The default is
+    ///     <see cref="CursorVisibility.Invisible"/>.
+    /// </summary>
+    public CursorVisibility CursorVisibility { get; set; } = CursorVisibility.Invisible;
+
+    /// <summary>
+    ///     Positions the cursor in the right position based on the currently focused view in the chain.
+    /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         Views that are focusable should override <see cref="PositionCursor()"/> to make sure that the cursor is
+    ///         placed in a location that makes sense. Some terminals do not have a way of hiding the cursor, so it can be
+    ///         distracting to have the cursor left at the last focused view. So views should make sure that they place the
+    ///         cursor in a visually sensible place. The default implementation of <see cref="PositionCursor()"/> will place the
+    ///         cursor at either the hotkey (if defined) or <c>0,0</c>.
+    ///     </para>
+    /// </remarks>
+    /// <returns>Viewport-relative cursor position. Return <see langword="null"/> to ensure the cursor is not visible.</returns>
+    public virtual Point? PositionCursor ()
+    {
+        if (IsInitialized && CanFocus && HasFocus)
+        {
+            // By default, position the cursor at the hotkey (if any) or 0, 0.
+            Move (TextFormatter.HotKeyPos == -1 ? 0 : TextFormatter.CursorPosition, 0);
+        }
+
+        // Returning null will hide the cursor.
+        return null;
+    }
+}
diff --git a/Terminal.Gui/View/ViewDiagnostics.cs b/Terminal.Gui/View/View.Diagnostics.cs
similarity index 100%
rename from Terminal.Gui/View/ViewDiagnostics.cs
rename to Terminal.Gui/View/View.Diagnostics.cs
diff --git a/Terminal.Gui/View/ViewDrawing.cs b/Terminal.Gui/View/View.Drawing.cs
similarity index 99%
rename from Terminal.Gui/View/ViewDrawing.cs
rename to Terminal.Gui/View/View.Drawing.cs
index 73fa5d550..1077f3917 100644
--- a/Terminal.Gui/View/ViewDrawing.cs
+++ b/Terminal.Gui/View/View.Drawing.cs
@@ -2,7 +2,7 @@
 
 namespace Terminal.Gui;
 
-public partial class View
+public partial class View // Drawing APIs
 {
     private ColorScheme _colorScheme;
 
diff --git a/Terminal.Gui/View/View.Hierarchy.cs b/Terminal.Gui/View/View.Hierarchy.cs
new file mode 100644
index 000000000..125baf33f
--- /dev/null
+++ b/Terminal.Gui/View/View.Hierarchy.cs
@@ -0,0 +1,320 @@
+namespace Terminal.Gui;
+
+public partial class View // SuperView/SubView hierarchy management (SuperView, SubViews, Add, Remove, etc.)
+{
+    private static readonly IList<View> _empty = new List<View> (0).AsReadOnly ();
+    internal bool _addingView;
+    private List<View> _subviews; // This is null, and allocated on demand.
+    private View _superView;
+
+    /// <summary>Indicates whether the view was added to <see cref="SuperView"/>.</summary>
+    public bool IsAdded { get; private set; }
+
+    /// <summary>This returns a list of the subviews contained by this view.</summary>
+    /// <value>The subviews.</value>
+    public IList<View> Subviews => _subviews?.AsReadOnly () ?? _empty;
+
+    /// <summary>Returns the container for this view, or null if this view has not been added to a container.</summary>
+    /// <value>The super view.</value>
+    public virtual View SuperView
+    {
+        get => _superView;
+        set => throw new NotImplementedException ();
+    }
+
+    // Internally, we use InternalSubviews rather than subviews, as we do not expect us
+    // to make the same mistakes our users make when they poke at the Subviews.
+    internal IList<View> InternalSubviews => _subviews ?? _empty;
+
+    /// <summary>Adds a subview (child) to this view.</summary>
+    /// <remarks>
+    ///     <para>
+    ///         The Views that have been added to this view can be retrieved via the <see cref="Subviews"/> property. See also
+    ///         <seealso cref="Remove(View)"/> <seealso cref="RemoveAll"/>
+    ///     </para>
+    ///     <para>
+    ///         Subviews will be disposed when this View is disposed. In other-words, calling this method causes
+    ///         the lifecycle of the subviews to be transferred to this View.
+    ///     </para>
+    /// </remarks>
+    /// <param name="view">The view to add.</param>
+    /// <returns>The view that was added.</returns>
+    public virtual View Add (View view)
+    {
+        if (view is null)
+        {
+            return view;
+        }
+
+        if (_subviews is null)
+        {
+            _subviews = new ();
+        }
+
+        if (_tabIndexes is null)
+        {
+            _tabIndexes = new ();
+        }
+
+        _subviews.Add (view);
+        _tabIndexes.Add (view);
+        view._superView = this;
+
+        if (view.CanFocus)
+        {
+            _addingView = true;
+
+            if (SuperView?.CanFocus == false)
+            {
+                SuperView._addingView = true;
+                SuperView.CanFocus = true;
+                SuperView._addingView = false;
+            }
+
+            // QUESTION: This automatic behavior of setting CanFocus to true on the SuperView is not documented, and is annoying.
+            CanFocus = true;
+            view._tabIndex = _tabIndexes.IndexOf (view);
+            _addingView = false;
+        }
+
+        if (view.Enabled && !Enabled)
+        {
+            view._oldEnabled = true;
+            view.Enabled = false;
+        }
+
+        OnAdded (new (this, view));
+
+        if (IsInitialized && !view.IsInitialized)
+        {
+            view.BeginInit ();
+            view.EndInit ();
+        }
+
+        CheckDimAuto ();
+        SetNeedsLayout ();
+        SetNeedsDisplay ();
+
+        return view;
+    }
+
+    /// <summary>Adds the specified views (children) to the view.</summary>
+    /// <param name="views">Array of one or more views (can be optional parameter).</param>
+    /// <remarks>
+    ///     <para>
+    ///         The Views that have been added to this view can be retrieved via the <see cref="Subviews"/> property. See also
+    ///         <seealso cref="Remove(View)"/> and <seealso cref="RemoveAll"/>.
+    ///     </para>
+    ///     <para>
+    ///         Subviews will be disposed when this View is disposed. In other-words, calling this method causes
+    ///         the lifecycle of the subviews to be transferred to this View.
+    ///     </para>
+    /// </remarks>
+    public void Add (params View [] views)
+    {
+        if (views is null)
+        {
+            return;
+        }
+
+        foreach (View view in views)
+        {
+            Add (view);
+        }
+    }
+
+    /// <summary>Event fired when this view is added to another.</summary>
+    public event EventHandler<SuperViewChangedEventArgs> Added;
+
+    /// <summary>Get the top superview of a given <see cref="View"/>.</summary>
+    /// <returns>The superview view.</returns>
+    public View GetTopSuperView (View view = null, View superview = null)
+    {
+        View top = superview ?? Application.Top;
+
+        for (View v = view?.SuperView ?? this?.SuperView; v != null; v = v.SuperView)
+        {
+            top = v;
+
+            if (top == superview)
+            {
+                break;
+            }
+        }
+
+        return top;
+    }
+
+    /// <summary>Method invoked when a subview is being added to this view.</summary>
+    /// <param name="e">Event where <see cref="ViewEventArgs.View"/> is the subview being added.</param>
+    public virtual void OnAdded (SuperViewChangedEventArgs e)
+    {
+        View view = e.Child;
+        view.IsAdded = true;
+        view.OnResizeNeeded ();
+        view.Added?.Invoke (this, e);
+    }
+
+    /// <summary>Method invoked when a subview is being removed from this view.</summary>
+    /// <param name="e">Event args describing the subview being removed.</param>
+    public virtual void OnRemoved (SuperViewChangedEventArgs e)
+    {
+        View view = e.Child;
+        view.IsAdded = false;
+        view.Removed?.Invoke (this, e);
+    }
+
+    /// <summary>Removes a subview added via <see cref="Add(View)"/> or <see cref="Add(View[])"/> from this View.</summary>
+    /// <remarks>
+    ///     <para>
+    ///         Normally Subviews will be disposed when this View is disposed. Removing a Subview causes ownership of the
+    ///         Subview's
+    ///         lifecycle to be transferred to the caller; the caller muse call <see cref="Dispose"/>.
+    ///     </para>
+    /// </remarks>
+    public virtual View Remove (View view)
+    {
+        if (view is null || _subviews is null)
+        {
+            return view;
+        }
+
+        Rectangle touched = view.Frame;
+        _subviews.Remove (view);
+        _tabIndexes.Remove (view);
+        view._superView = null;
+        view._tabIndex = -1;
+        SetNeedsLayout ();
+        SetNeedsDisplay ();
+
+        foreach (View v in _subviews)
+        {
+            if (v.Frame.IntersectsWith (touched))
+            {
+                view.SetNeedsDisplay ();
+            }
+        }
+
+        OnRemoved (new (this, view));
+
+        if (Focused == view)
+        {
+            Focused = null;
+        }
+
+        return view;
+    }
+
+    /// <summary>
+    ///     Removes all subviews (children) added via <see cref="Add(View)"/> or <see cref="Add(View[])"/> from this View.
+    /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         Normally Subviews will be disposed when this View is disposed. Removing a Subview causes ownership of the
+    ///         Subview's
+    ///         lifecycle to be transferred to the caller; the caller must call <see cref="Dispose"/> on any Views that were
+    ///         added.
+    ///     </para>
+    /// </remarks>
+    public virtual void RemoveAll ()
+    {
+        if (_subviews is null)
+        {
+            return;
+        }
+
+        while (_subviews.Count > 0)
+        {
+            Remove (_subviews [0]);
+        }
+    }
+
+    /// <summary>Event fired when this view is removed from another.</summary>
+    public event EventHandler<SuperViewChangedEventArgs> Removed;
+
+
+    /// <summary>Moves <paramref name="subview"/> one position towards the start of the <see cref="Subviews"/> list</summary>
+    /// <param name="subview">The subview to move forward.</param>
+    public void BringSubviewForward (View subview)
+    {
+        PerformActionForSubview (
+                                 subview,
+                                 x =>
+                                 {
+                                     int idx = _subviews.IndexOf (x);
+
+                                     if (idx + 1 < _subviews.Count)
+                                     {
+                                         _subviews.Remove (x);
+                                         _subviews.Insert (idx + 1, x);
+                                     }
+                                 }
+                                );
+    }
+
+    /// <summary>Moves <paramref name="subview"/> to the start of the <see cref="Subviews"/> list.</summary>
+    /// <param name="subview">The subview to send to the start.</param>
+    public void BringSubviewToFront (View subview)
+    {
+        PerformActionForSubview (
+                                 subview,
+                                 x =>
+                                 {
+                                     _subviews.Remove (x);
+                                     _subviews.Add (x);
+                                 }
+                                );
+    }
+
+
+    /// <summary>Moves <paramref name="subview"/> one position towards the end of the <see cref="Subviews"/> list</summary>
+    /// <param name="subview">The subview to move backwards.</param>
+    public void SendSubviewBackwards (View subview)
+    {
+        PerformActionForSubview (
+                                 subview,
+                                 x =>
+                                 {
+                                     int idx = _subviews.IndexOf (x);
+
+                                     if (idx > 0)
+                                     {
+                                         _subviews.Remove (x);
+                                         _subviews.Insert (idx - 1, x);
+                                     }
+                                 }
+                                );
+    }
+
+    /// <summary>Moves <paramref name="subview"/> to the end of the <see cref="Subviews"/> list.</summary>
+    /// <param name="subview">The subview to send to the end.</param>
+    public void SendSubviewToBack (View subview)
+    {
+        PerformActionForSubview (
+                                 subview,
+                                 x =>
+                                 {
+                                     _subviews.Remove (x);
+                                     _subviews.Insert (0, subview);
+                                 }
+                                );
+    }
+
+    /// <summary>
+    ///     Internal API that runs <paramref name="action"/> on a subview if it is part of the <see cref="Subviews"/> list.
+    /// </summary>
+    /// <param name="subview"></param>
+    /// <param name="action"></param>
+    private void PerformActionForSubview (View subview, Action<View> action)
+    {
+        if (_subviews.Contains (subview))
+        {
+            action (subview);
+        }
+
+        // BUGBUG: this is odd. Why is this needed?
+        SetNeedsDisplay ();
+        subview.SetNeedsDisplay ();
+    }
+
+}
diff --git a/Terminal.Gui/View/ViewKeyboard.cs b/Terminal.Gui/View/View.Keyboard.cs
similarity index 91%
rename from Terminal.Gui/View/ViewKeyboard.cs
rename to Terminal.Gui/View/View.Keyboard.cs
index 7a905f129..7009ab4c6 100644
--- a/Terminal.Gui/View/ViewKeyboard.cs
+++ b/Terminal.Gui/View/View.Keyboard.cs
@@ -3,7 +3,7 @@ using System.Diagnostics;
 
 namespace Terminal.Gui;
 
-public partial class View
+public partial class View  // Keyboard APIs
 {
     /// <summary>
     ///  Helper to configure all things keyboard related for a View. Called from the View constructor.
@@ -254,119 +254,6 @@ public partial class View
 
     #endregion HotKey Support
 
-    #region Tab/Focus Handling
-
-    // This is null, and allocated on demand.
-    private List<View> _tabIndexes;
-
-    /// <summary>Gets a list of the subviews that are <see cref="TabStop"/>s.</summary>
-    /// <value>The tabIndexes.</value>
-    public IList<View> TabIndexes => _tabIndexes?.AsReadOnly () ?? _empty;
-
-    private int _tabIndex = -1;
-    private int _oldTabIndex;
-
-    /// <summary>
-    ///     Indicates the index of the current <see cref="View"/> from the <see cref="TabIndexes"/> list. See also:
-    ///     <seealso cref="TabStop"/>.
-    /// </summary>
-    public int TabIndex
-    {
-        get => _tabIndex;
-        set
-        {
-            if (!CanFocus)
-            {
-                _tabIndex = -1;
-
-                return;
-            }
-
-            if (SuperView?._tabIndexes is null || SuperView?._tabIndexes.Count == 1)
-            {
-                _tabIndex = 0;
-
-                return;
-            }
-
-            if (_tabIndex == value && TabIndexes.IndexOf (this) == value)
-            {
-                return;
-            }
-
-            _tabIndex = value > SuperView._tabIndexes.Count - 1 ? SuperView._tabIndexes.Count - 1 :
-                        value < 0 ? 0 : value;
-            _tabIndex = GetTabIndex (_tabIndex);
-
-            if (SuperView._tabIndexes.IndexOf (this) != _tabIndex)
-            {
-                SuperView._tabIndexes.Remove (this);
-                SuperView._tabIndexes.Insert (_tabIndex, this);
-                SetTabIndex ();
-            }
-        }
-    }
-
-    private int GetTabIndex (int idx)
-    {
-        var i = 0;
-
-        foreach (View v in SuperView._tabIndexes)
-        {
-            if (v._tabIndex == -1 || v == this)
-            {
-                continue;
-            }
-
-            i++;
-        }
-
-        return Math.Min (i, idx);
-    }
-
-    private void SetTabIndex ()
-    {
-        var i = 0;
-
-        foreach (View v in SuperView._tabIndexes)
-        {
-            if (v._tabIndex == -1)
-            {
-                continue;
-            }
-
-            v._tabIndex = i;
-            i++;
-        }
-    }
-
-    private bool _tabStop = true;
-
-    /// <summary>
-    ///     Gets or sets whether the view is a stop-point for keyboard navigation of focus. Will be <see langword="true"/>
-    ///     only if the <see cref="CanFocus"/> is also <see langword="true"/>. Set to <see langword="false"/> to prevent the
-    ///     view from being a stop-point for keyboard navigation.
-    /// </summary>
-    /// <remarks>
-    ///     The default keyboard navigation keys are <c>Key.Tab</c> and <c>Key>Tab.WithShift</c>. These can be changed by
-    ///     modifying the key bindings (see <see cref="KeyBindings.Add(Key, Command[])"/>) of the SuperView.
-    /// </remarks>
-    public bool TabStop
-    {
-        get => _tabStop;
-        set
-        {
-            if (_tabStop == value)
-            {
-                return;
-            }
-
-            _tabStop = CanFocus && value;
-        }
-    }
-
-    #endregion Tab/Focus Handling
-
     #region Low-level Key handling
 
     #region Key Down Event
diff --git a/Terminal.Gui/View/Layout/ViewLayout.cs b/Terminal.Gui/View/View.Layout.cs
similarity index 99%
rename from Terminal.Gui/View/Layout/ViewLayout.cs
rename to Terminal.Gui/View/View.Layout.cs
index 72a9bf14c..deb7da682 100644
--- a/Terminal.Gui/View/Layout/ViewLayout.cs
+++ b/Terminal.Gui/View/View.Layout.cs
@@ -3,7 +3,7 @@ using System.Diagnostics;
 
 namespace Terminal.Gui;
 
-public partial class View
+public partial class View // Layout APIs
 {
     #region Frame
 
diff --git a/Terminal.Gui/View/ViewMouse.cs b/Terminal.Gui/View/View.Mouse.cs
similarity index 99%
rename from Terminal.Gui/View/ViewMouse.cs
rename to Terminal.Gui/View/View.Mouse.cs
index 24314f583..5f1318e21 100644
--- a/Terminal.Gui/View/ViewMouse.cs
+++ b/Terminal.Gui/View/View.Mouse.cs
@@ -2,7 +2,7 @@
 
 namespace Terminal.Gui;
 
-public partial class View
+public partial class View // Mouse APIs
 {
     [CanBeNull]
     private ColorScheme _savedHighlightColorScheme;
diff --git a/Terminal.Gui/View/View.Navigation.cs b/Terminal.Gui/View/View.Navigation.cs
new file mode 100644
index 000000000..4ff99c3d7
--- /dev/null
+++ b/Terminal.Gui/View/View.Navigation.cs
@@ -0,0 +1,813 @@
+namespace Terminal.Gui;
+
+public partial class View // Focus and cross-view navigation management (TabStop, TabIndex, etc...)
+{
+    /// <summary>Returns a value indicating if this View is currently on Top (Active)</summary>
+    public bool IsCurrentTop => Application.Current == this;
+
+    // BUGBUG: This API is poorly defined and implemented. It deeply intertwines the view hierarchy with the tab order.
+    /// <summary>Exposed as `internal` for unit tests. Indicates focus navigation direction.</summary>
+    internal enum NavigationDirection
+    {
+        /// <summary>Navigate forward.</summary>
+        Forward,
+
+        /// <summary>Navigate backwards.</summary>
+        Backward
+    }
+
+    /// <summary>Invoked when this view is gaining focus (entering).</summary>
+    /// <param name="leavingView">The view that is leaving focus.</param>
+    /// <returns> <see langword="true"/>, if the event was handled, <see langword="false"/> otherwise.</returns>
+    /// <remarks>
+    ///     <para>
+    ///         Overrides must call the base class method to ensure that the <see cref="Enter"/> event is raised. If the event
+    ///         is handled, the method should return <see langword="true"/>.
+    ///     </para>
+    /// </remarks>
+    public virtual bool OnEnter (View leavingView)
+    {
+        var args = new FocusEventArgs (leavingView, this);
+        Enter?.Invoke (this, args);
+
+        if (args.Handled)
+        {
+            return true;
+        }
+
+        return false;
+    }
+
+    /// <summary>Invoked when this view is losing focus (leaving).</summary>
+    /// <param name="enteringView">The view that is entering focus.</param>
+    /// <returns> <see langword="true"/>, if the event was handled, <see langword="false"/> otherwise.</returns>
+    /// <remarks>
+    ///     <para>
+    ///         Overrides must call the base class method to ensure that the <see cref="Leave"/> event is raised. If the event
+    ///         is handled, the method should return <see langword="true"/>.
+    ///     </para>
+    /// </remarks>
+    public virtual bool OnLeave (View enteringView)
+    {
+        var args = new FocusEventArgs (this, enteringView);
+        Leave?.Invoke (this, args);
+
+        if (args.Handled)
+        {
+            return true;
+        }
+
+        return false;
+    }
+
+    /// <summary>Raised when the view is gaining (entering) focus. Can be cancelled.</summary>
+    /// <remarks>
+    ///     Raised by the <see cref="OnEnter"/> virtual method.
+    /// </remarks>
+    public event EventHandler<FocusEventArgs> Enter;
+
+    /// <summary>Raised when the view is losing (leaving) focus. Can be cancelled.</summary>
+    /// <remarks>
+    ///     Raised by the <see cref="OnLeave"/> virtual method.
+    /// </remarks>
+    public event EventHandler<FocusEventArgs> Leave;
+
+    private NavigationDirection _focusDirection;
+
+    /// <summary>
+    ///     Gets or sets the focus direction for this view and all subviews.
+    ///     Setting this property will set the focus direction for all views up the SuperView hierarchy.
+    /// </summary>
+    internal NavigationDirection FocusDirection
+    {
+        get => SuperView?.FocusDirection ?? _focusDirection;
+        set
+        {
+            if (SuperView is { })
+            {
+                SuperView.FocusDirection = value;
+            }
+            else
+            {
+                _focusDirection = value;
+            }
+        }
+    }
+
+    private bool _hasFocus;
+
+    /// <summary>
+    ///     Gets or sets whether this view has focus.
+    /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         Causes the <see cref="OnEnter"/> and <see cref="OnLeave"/> virtual methods (and <see cref="Enter"/> and
+    ///         <see cref="Leave"/> events to be raised) when the value changes.
+    ///     </para>
+    ///     <para>
+    ///         Setting this property to <see langword="false"/> will recursively set <see cref="HasFocus"/> to
+    ///         <see langword="false"/>
+    ///         for any focused subviews.
+    ///     </para>
+    /// </remarks>
+    public bool HasFocus
+    {
+        // Force the specified view to have focus
+        set => SetHasFocus (value, this, true);
+        get => _hasFocus;
+    }
+
+    /// <summary>
+    ///     Internal API that sets <see cref="HasFocus"/>. This method is called by <c>HasFocus_set</c> and other methods that
+    ///     need to set or remove focus from a view.
+    /// </summary>
+    /// <param name="newHasFocus">The new setting for <see cref="HasFocus"/>.</param>
+    /// <param name="view">The view that will be gaining or losing focus.</param>
+    /// <param name="force">
+    ///     <see langword="true"/> to force Enter/Leave on <paramref name="view"/> regardless of whether it
+    ///     already HasFocus or not.
+    /// </param>
+    /// <remarks>
+    ///     If <paramref name="newHasFocus"/> is <see langword="false"/> and there is a focused subview (<see cref="Focused"/>
+    ///     is not <see langword="null"/>),
+    ///     this method will recursively remove focus from any focused subviews of <see cref="Focused"/>.
+    /// </remarks>
+    private void SetHasFocus (bool newHasFocus, View view, bool force = false)
+    {
+        if (HasFocus != newHasFocus || force)
+        {
+            _hasFocus = newHasFocus;
+
+            if (newHasFocus)
+            {
+                OnEnter (view);
+            }
+            else
+            {
+                OnLeave (view);
+            }
+
+            SetNeedsDisplay ();
+        }
+
+        // Remove focus down the chain of subviews if focus is removed
+        if (!newHasFocus && Focused is { })
+        {
+            View f = Focused;
+            f.OnLeave (view);
+            f.SetHasFocus (false, view);
+            Focused = null;
+        }
+    }
+
+    /// <summary>Raised when <see cref="CanFocus"/> has been changed.</summary>
+    /// <remarks>
+    ///     Raised by the <see cref="OnCanFocusChanged"/> virtual method.
+    /// </remarks>
+    public event EventHandler CanFocusChanged;
+
+    /// <summary>Invoked when the <see cref="CanFocus"/> property from a view is changed.</summary>
+    /// <remarks>
+    ///     Raises the <see cref="CanFocusChanged"/> event.
+    /// </remarks>
+    public virtual void OnCanFocusChanged () { CanFocusChanged?.Invoke (this, EventArgs.Empty); }
+
+    private bool _oldCanFocus;
+    private bool _canFocus;
+
+    /// <summary>Gets or sets a value indicating whether this <see cref="View"/> can be focused.</summary>
+    /// <remarks>
+    ///     <para>
+    ///         <see cref="SuperView"/> must also have <see cref="CanFocus"/> set to <see langword="true"/>.
+    ///     </para>
+    /// </remarks>
+    public bool CanFocus
+    {
+        get => _canFocus;
+        set
+        {
+            if (!_addingView && IsInitialized && SuperView?.CanFocus == false && value)
+            {
+                throw new InvalidOperationException ("Cannot set CanFocus to true if the SuperView CanFocus is false!");
+            }
+
+            if (_canFocus == value)
+            {
+                return;
+            }
+
+            _canFocus = value;
+
+            switch (_canFocus)
+            {
+                case false when _tabIndex > -1:
+                    TabIndex = -1;
+
+                    break;
+                case true when SuperView?.CanFocus == false && _addingView:
+                    SuperView.CanFocus = true;
+
+                    break;
+            }
+
+            if (_canFocus && _tabIndex == -1)
+            {
+                TabIndex = SuperView is { } ? SuperView._tabIndexes.IndexOf (this) : -1;
+            }
+
+            TabStop = _canFocus;
+
+            if (!_canFocus && SuperView?.Focused == this)
+            {
+                SuperView.Focused = null;
+            }
+
+            if (!_canFocus && HasFocus)
+            {
+                SetHasFocus (false, this);
+                SuperView?.EnsureFocus ();
+
+                if (SuperView is { Focused: null })
+                {
+                    SuperView.FocusNext ();
+
+                    if (SuperView.Focused is null && Application.Current is { })
+                    {
+                        Application.Current.FocusNext ();
+                    }
+
+                    ApplicationOverlapped.BringOverlappedTopToFront ();
+                }
+            }
+
+            if (_subviews is { } && IsInitialized)
+            {
+                foreach (View view in _subviews)
+                {
+                    if (view.CanFocus != value)
+                    {
+                        if (!value)
+                        {
+                            view._oldCanFocus = view.CanFocus;
+                            view._oldTabIndex = view._tabIndex;
+                            view.CanFocus = false;
+                            view._tabIndex = -1;
+                        }
+                        else
+                        {
+                            if (_addingView)
+                            {
+                                view._addingView = true;
+                            }
+
+                            view.CanFocus = view._oldCanFocus;
+                            view._tabIndex = view._oldTabIndex;
+                            view._addingView = false;
+                        }
+                    }
+                }
+
+                if (this is Toplevel && Application.Current.Focused != this)
+                {
+                    ApplicationOverlapped.BringOverlappedTopToFront ();
+                }
+            }
+
+            OnCanFocusChanged ();
+            SetNeedsDisplay ();
+        }
+    }
+
+    /// <summary>Returns the currently focused Subview inside this view, or <see langword="null"/> if nothing is focused.</summary>
+    /// <value>The currently focused Subview.</value>
+    public View Focused { get; private set; }
+
+    /// <summary>
+    ///     Returns the most focused Subview in the chain of subviews (the leaf view that has the focus), or
+    ///     <see langword="null"/> if nothing is focused.
+    /// </summary>
+    /// <value>The most focused Subview.</value>
+    public View MostFocused
+    {
+        get
+        {
+            if (Focused is null)
+            {
+                return null;
+            }
+
+            View most = Focused.MostFocused;
+
+            if (most is { })
+            {
+                return most;
+            }
+
+            return Focused;
+        }
+    }
+
+    /// <summary>Causes subview specified by <paramref name="view"/> to enter focus.</summary>
+    /// <param name="view">View.</param>
+    private void SetFocus (View view)
+    {
+        if (view is null)
+        {
+            return;
+        }
+
+        //Console.WriteLine ($"Request to focus {view}");
+        if (!view.CanFocus || !view.Visible || !view.Enabled)
+        {
+            return;
+        }
+
+        if (Focused?._hasFocus == true && Focused == view)
+        {
+            return;
+        }
+
+        if ((Focused?._hasFocus == true && Focused?.SuperView == view) || view == this)
+        {
+            if (!view._hasFocus)
+            {
+                view._hasFocus = true;
+            }
+
+            return;
+        }
+
+        // Make sure that this view is a subview
+        View c;
+
+        for (c = view._superView; c != null; c = c._superView)
+        {
+            if (c == this)
+            {
+                break;
+            }
+        }
+
+        if (c is null)
+        {
+            throw new ArgumentException ("the specified view is not part of the hierarchy of this view");
+        }
+
+        if (Focused is { })
+        {
+            Focused.SetHasFocus (false, view);
+        }
+
+        View f = Focused;
+        Focused = view;
+        Focused.SetHasFocus (true, f);
+        Focused.EnsureFocus ();
+
+        // Send focus upwards
+        if (SuperView is { })
+        {
+            SuperView.SetFocus (this);
+        }
+        else
+        {
+            SetFocus (this);
+        }
+    }
+
+    /// <summary>Causes this view to be focused and entire Superview hierarchy to have the focused order updated.</summary>
+    public void SetFocus ()
+    {
+        if (!CanBeVisible (this) || !Enabled)
+        {
+            if (HasFocus)
+            {
+                SetHasFocus (false, this);
+            }
+
+            return;
+        }
+
+        if (SuperView is { })
+        {
+            SuperView.SetFocus (this);
+        }
+        else
+        {
+            SetFocus (this);
+        }
+    }
+
+    /// <summary>
+    ///     If there is no focused subview, calls <see cref="FocusFirst"/> or <see cref="FocusLast"/> based on
+    ///     <see cref="FocusDirection"/>.
+    ///     does nothing.
+    /// </summary>
+    public void EnsureFocus ()
+    {
+        if (Focused is null && _subviews?.Count > 0)
+        {
+            if (FocusDirection == NavigationDirection.Forward)
+            {
+                FocusFirst ();
+            }
+            else
+            {
+                FocusLast ();
+            }
+        }
+    }
+
+    /// <summary>
+    ///     Focuses the last focusable view in <see cref="View.TabIndexes"/> if one exists. If there are no views in
+    ///     <see cref="View.TabIndexes"/> then the focus is set to the view itself.
+    /// </summary>
+    public void FocusFirst (bool overlapped = false)
+    {
+        if (!CanBeVisible (this))
+        {
+            return;
+        }
+
+        if (_tabIndexes is null)
+        {
+            SuperView?.SetFocus (this);
+
+            return;
+        }
+
+        foreach (View view in _tabIndexes.Where (v => !overlapped || v.Arrangement.HasFlag (ViewArrangement.Overlapped)))
+        {
+            if (view.CanFocus && view._tabStop && view.Visible && view.Enabled)
+            {
+                SetFocus (view);
+
+                return;
+            }
+        }
+    }
+
+    /// <summary>
+    ///     Focuses the last focusable view in <see cref="View.TabIndexes"/> if one exists. If there are no views in
+    ///     <see cref="View.TabIndexes"/> then the focus is set to the view itself.
+    /// </summary>
+    public void FocusLast (bool overlapped = false)
+    {
+        if (!CanBeVisible (this))
+        {
+            return;
+        }
+
+        if (_tabIndexes is null)
+        {
+            SuperView?.SetFocus (this);
+
+            return;
+        }
+
+        foreach (View view in _tabIndexes.Where (v => !overlapped || v.Arrangement.HasFlag (ViewArrangement.Overlapped)).Reverse ())
+        {
+            if (view.CanFocus && view._tabStop && view.Visible && view.Enabled)
+            {
+                SetFocus (view);
+
+                return;
+            }
+        }
+    }
+
+    /// <summary>
+    ///     Focuses the previous view in <see cref="View.TabIndexes"/>. If there is no previous view, the focus is set to the
+    ///     view itself.
+    /// </summary>
+    /// <returns><see langword="true"/> if previous was focused, <see langword="false"/> otherwise.</returns>
+    public bool FocusPrev ()
+    {
+        if (!CanBeVisible (this))
+        {
+            return false;
+        }
+
+        FocusDirection = NavigationDirection.Backward;
+
+        if (TabIndexes is null || TabIndexes.Count == 0)
+        {
+            return false;
+        }
+
+        if (Focused is null)
+        {
+            FocusLast ();
+
+            return Focused != null;
+        }
+
+        int focusedIdx = -1;
+
+        for (int i = TabIndexes.Count; i > 0;)
+        {
+            i--;
+            View w = TabIndexes [i];
+
+            if (w.HasFocus)
+            {
+                if (w.FocusPrev ())
+                {
+                    return true;
+                }
+
+                focusedIdx = i;
+
+                continue;
+            }
+
+            if (w.CanFocus && focusedIdx != -1 && w._tabStop && w.Visible && w.Enabled)
+            {
+                Focused.SetHasFocus (false, w);
+
+                // If the focused view is overlapped don't focus on the next if it's not overlapped.
+                if (Focused.Arrangement.HasFlag (ViewArrangement.Overlapped) && !w.Arrangement.HasFlag (ViewArrangement.Overlapped))
+                {
+                    FocusLast (true);
+
+                    return true;
+                }
+
+                // If the focused view is not overlapped and the next is, skip it
+                if (!Focused.Arrangement.HasFlag (ViewArrangement.Overlapped) && w.Arrangement.HasFlag (ViewArrangement.Overlapped))
+                {
+                    continue;
+                }
+
+                if (w.CanFocus && w._tabStop && w.Visible && w.Enabled)
+                {
+                    w.FocusLast ();
+                }
+
+                SetFocus (w);
+
+                return true;
+            }
+        }
+
+        // There's no prev view in tab indexes.
+        if (Focused is { })
+        {
+            // Leave Focused
+            Focused.SetHasFocus (false, this);
+
+            if (Focused.Arrangement.HasFlag (ViewArrangement.Overlapped))
+            {
+                FocusLast (true);
+
+                return true;
+            }
+
+            // Signal to caller no next view was found
+            Focused = null;
+        }
+
+        return false;
+    }
+
+    /// <summary>
+    ///     Focuses the next view in <see cref="View.TabIndexes"/>. If there is no next view, the focus is set to the view
+    ///     itself.
+    /// </summary>
+    /// <returns><see langword="true"/> if next was focused, <see langword="false"/> otherwise.</returns>
+    public bool FocusNext ()
+    {
+        if (!CanBeVisible (this))
+        {
+            return false;
+        }
+
+        FocusDirection = NavigationDirection.Forward;
+
+        if (TabIndexes is null || TabIndexes.Count == 0)
+        {
+            return false;
+        }
+
+        if (Focused is null)
+        {
+            FocusFirst ();
+
+            return Focused != null;
+        }
+
+        int focusedIdx = -1;
+
+        for (var i = 0; i < TabIndexes.Count; i++)
+        {
+            View w = TabIndexes [i];
+
+            if (w.HasFocus)
+            {
+                if (w.FocusNext ())
+                {
+                    return true;
+                }
+
+                focusedIdx = i;
+
+                continue;
+            }
+
+            if (w.CanFocus && focusedIdx != -1 && w._tabStop && w.Visible && w.Enabled)
+            {
+                Focused.SetHasFocus (false, w);
+
+                //// If the focused view is overlapped don't focus on the next if it's not overlapped.
+                //if (Focused.Arrangement.HasFlag (ViewArrangement.Overlapped)/* && !w.Arrangement.HasFlag (ViewArrangement.Overlapped)*/)
+                //{
+                //    return false;
+                //}
+
+                //// If the focused view is not overlapped and the next is, skip it
+                //if (!Focused.Arrangement.HasFlag (ViewArrangement.Overlapped) && w.Arrangement.HasFlag (ViewArrangement.Overlapped))
+                //{
+                //    continue;
+                //}
+
+                if (w.CanFocus && w._tabStop && w.Visible && w.Enabled)
+                {
+                    w.FocusFirst ();
+                }
+
+                SetFocus (w);
+
+                return true;
+            }
+        }
+
+        // There's no next view in tab indexes.
+        if (Focused is { })
+        {
+            // Leave Focused
+            Focused.SetHasFocus (false, this);
+
+            //if (Focused.Arrangement.HasFlag (ViewArrangement.Overlapped))
+            //{
+            //    FocusFirst (true);
+            //    return true;
+            //}
+
+            // Signal to caller no next view was found
+            Focused = null;
+        }
+
+        return false;
+    }
+
+    private View GetMostFocused (View view)
+    {
+        if (view is null)
+        {
+            return null;
+        }
+
+        return view.Focused is { } ? GetMostFocused (view.Focused) : view;
+    }
+
+    #region Tab/Focus Handling
+
+    private List<View> _tabIndexes;
+
+    // TODO: This should be a get-only property?
+    // BUGBUG: This returns an AsReadOnly list, but isn't declared as such.
+    /// <summary>Gets a list of the subviews that are a <see cref="TabStop"/>.</summary>
+    /// <value>The tabIndexes.</value>
+    public IList<View> TabIndexes => _tabIndexes?.AsReadOnly () ?? _empty;
+
+    // TODO: Change this to int? and use null to indicate the view is not in the tab order.
+    private int _tabIndex = -1;
+    private int _oldTabIndex;
+
+    /// <summary>
+    ///     Indicates the index of the current <see cref="View"/> from the <see cref="TabIndexes"/> list. See also:
+    ///     <seealso cref="TabStop"/>.
+    /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         If the value is -1, the view is not part of the tab order.
+    ///     </para>
+    ///     <para>
+    ///         On set, if <see cref="CanFocus"/> is <see langword="false"/>, <see cref="TabIndex"/> will be set to -1.
+    ///     </para>
+    ///     <para>
+    ///         On set, if <see cref="SuperView"/> is <see langword="null"/> or has not TabStops, <see cref="TabIndex"/> will
+    ///         be set to 0.
+    ///     </para>
+    ///     <para>
+    ///         On set, if <see cref="SuperView"/> has only one TabStop, <see cref="TabIndex"/> will be set to 0.
+    ///     </para>
+    /// </remarks>
+    public int TabIndex
+    {
+        get => _tabIndex;
+        set
+        {
+            if (!CanFocus)
+            {
+                // BUGBUG: Property setters should set the property to the value passed in and not have side effects.
+                _tabIndex = -1;
+
+                return;
+            }
+
+            if (SuperView?._tabIndexes is null || SuperView?._tabIndexes.Count == 1)
+            {
+                // BUGBUG: Property setters should set the property to the value passed in and not have side effects.
+                _tabIndex = 0;
+
+                return;
+            }
+
+            if (_tabIndex == value && TabIndexes.IndexOf (this) == value)
+            {
+                return;
+            }
+
+            _tabIndex = value > SuperView!.TabIndexes.Count - 1 ? SuperView._tabIndexes.Count - 1 :
+                        value < 0 ? 0 : value;
+            _tabIndex = GetGreatestTabIndexInSuperView (_tabIndex);
+
+            if (SuperView._tabIndexes.IndexOf (this) != _tabIndex)
+            {
+                // BUGBUG: we have to use _tabIndexes and not TabIndexes because TabIndexes returns is a read-only version of _tabIndexes
+                SuperView._tabIndexes.Remove (this);
+                SuperView._tabIndexes.Insert (_tabIndex, this);
+                ReorderSuperViewTabIndexes ();
+            }
+        }
+    }
+
+    /// <summary>
+    ///     Gets the greatest <see cref="TabIndex"/> of the <see cref="SuperView"/>'s <see cref="TabIndexes"/> that is less
+    ///     than or equal to <paramref name="idx"/>.
+    /// </summary>
+    /// <param name="idx"></param>
+    /// <returns>The minimum of <paramref name="idx"/> and the <see cref="SuperView"/>'s <see cref="TabIndexes"/>.</returns>
+    private int GetGreatestTabIndexInSuperView (int idx)
+    {
+        var i = 0;
+
+        foreach (View superViewTabStop in SuperView._tabIndexes)
+        {
+            if (superViewTabStop._tabIndex == -1 || superViewTabStop == this)
+            {
+                continue;
+            }
+
+            i++;
+        }
+
+        return Math.Min (i, idx);
+    }
+
+    /// <summary>
+    ///     Re-orders the <see cref="TabIndex"/>s of the views in the <see cref="SuperView"/>'s <see cref="TabIndexes"/>.
+    /// </summary>
+    private void ReorderSuperViewTabIndexes ()
+    {
+        var i = 0;
+
+        foreach (View superViewTabStop in SuperView._tabIndexes)
+        {
+            if (superViewTabStop._tabIndex == -1)
+            {
+                continue;
+            }
+
+            superViewTabStop._tabIndex = i;
+            i++;
+        }
+    }
+
+    private bool _tabStop = true;
+
+    /// <summary>
+    ///     Gets or sets whether the view is a stop-point for keyboard navigation of focus. Will be <see langword="true"/>
+    ///     only if <see cref="CanFocus"/> is <see langword="true"/>. Set to <see langword="false"/> to prevent the
+    ///     view from being a stop-point for keyboard navigation.
+    /// </summary>
+    /// <remarks>
+    ///     The default keyboard navigation keys are <c>Key.Tab</c> and <c>Key>Tab.WithShift</c>. These can be changed by
+    ///     modifying the key bindings (see <see cref="KeyBindings.Add(Key, Command[])"/>) of the SuperView.
+    /// </remarks>
+    public bool TabStop
+    {
+        get => _tabStop;
+        set
+        {
+            if (_tabStop == value)
+            {
+                return;
+            }
+
+            _tabStop = CanFocus && value;
+        }
+    }
+
+    #endregion Tab/Focus Handling
+}
diff --git a/Terminal.Gui/View/ViewText.cs b/Terminal.Gui/View/View.Text.cs
similarity index 99%
rename from Terminal.Gui/View/ViewText.cs
rename to Terminal.Gui/View/View.Text.cs
index 6b9e0cf94..664640730 100644
--- a/Terminal.Gui/View/ViewText.cs
+++ b/Terminal.Gui/View/View.Text.cs
@@ -2,7 +2,7 @@
 
 namespace Terminal.Gui;
 
-public partial class View
+public partial class View // Text Property APIs
 {
     /// <summary>
     ///    Initializes the Text of the View. Called by the constructor.
diff --git a/Terminal.Gui/View/ViewArrangement.cs b/Terminal.Gui/View/ViewArrangement.cs
index df13c4762..0143b082e 100644
--- a/Terminal.Gui/View/ViewArrangement.cs
+++ b/Terminal.Gui/View/ViewArrangement.cs
@@ -1,14 +1,16 @@
 namespace Terminal.Gui;
 
 /// <summary>
-///     Describes what user actions are enabled for arranging a <see cref="View"/> within it's <see cref="View.SuperView"/>.
+///     Describes what user actions are enabled for arranging a <see cref="View"/> within it's <see cref="View.SuperView"/>
+///     .
 ///     See <see cref="View.Arrangement"/>.
 /// </summary>
 /// <remarks>
-/// <para>
-///     Sizing or moving a view is only possible if the <see cref="View"/> is part of a <see cref="View.SuperView"/> and
-///     the relevant position and dimensions of the <see cref="View"/> are independent of other SubViews
-/// </para>
+///     <para>
+///         Sizing or moving a view is only possible if the <see cref="View"/> is part of a <see cref="View.SuperView"/>
+///         and
+///         the relevant position and dimensions of the <see cref="View"/> are independent of other SubViews
+///     </para>
 /// </remarks>
 [Flags]
 public enum ViewArrangement
@@ -56,26 +58,14 @@ public enum ViewArrangement
     Resizable = LeftResizable | RightResizable | TopResizable | BottomResizable,
 
     /// <summary>
-    ///    The view overlap other views.
+    ///     The view overlap other views.
     /// </summary>
     /// <remarks>
     ///     <para>
-    ///         When set, Tab and Shift-Tab will be constrained to the subviews of the view (normally, they will navigate to the next/prev view in the next/prev Tabindex).
+    ///         When set, Tab and Shift-Tab will be constrained to the subviews of the view (normally, they will navigate to
+    ///         the next/prev view in the next/prev Tabindex).
     ///         Use Ctrl-Tab (Ctrl-PageDown) / Ctrl-Shift-Tab (Ctrl-PageUp) to move between overlapped views.
     ///     </para>
     /// </remarks>
     Overlapped = 32
 }
-public partial class View
-{
-    /// <summary>
-    ///    Gets or sets the user actions that are enabled for the view within it's <see cref="SuperView"/>.
-    /// </summary>
-    /// <remarks>
-    /// <para>
-    ///     Sizing or moving a view is only possible if the <see cref="View"/> is part of a <see cref="SuperView"/> and
-    ///     the relevant position and dimensions of the <see cref="View"/> are independent of other SubViews
-    /// </para>
-    /// </remarks>
-    public ViewArrangement Arrangement { get; set; }
-}
diff --git a/Terminal.Gui/View/ViewEventArgs.cs b/Terminal.Gui/View/ViewEventArgs.cs
index b17b98afe..cdcbaa009 100644
--- a/Terminal.Gui/View/ViewEventArgs.cs
+++ b/Terminal.Gui/View/ViewEventArgs.cs
@@ -13,69 +13,4 @@ public class ViewEventArgs : EventArgs
     ///     child then sender may be the parent while <see cref="View"/> is the child being added.
     /// </remarks>
     public View View { get; }
-}
-
-/// <summary>Event arguments for the <see cref="View.LayoutComplete"/> event.</summary>
-public class LayoutEventArgs : EventArgs
-{
-    /// <summary>Creates a new instance of the <see cref="Terminal.Gui.LayoutEventArgs"/> class.</summary>
-    /// <param name="oldContentSize">The view that the event is about.</param>
-    public LayoutEventArgs (Size oldContentSize) { OldContentSize = oldContentSize; }
-
-    /// <summary>The viewport of the <see cref="View"/> before it was laid out.</summary>
-    public Size OldContentSize { get; set; }
-}
-
-/// <summary>Event args for draw events</summary>
-public class DrawEventArgs : EventArgs
-{
-    /// <summary>Creates a new instance of the <see cref="DrawEventArgs"/> class.</summary>
-    /// <param name="newViewport">
-    ///     The Content-relative rectangle describing the new visible viewport into the
-    ///     <see cref="View"/>.
-    /// </param>
-    /// <param name="oldViewport">
-    ///     The Content-relative rectangle describing the old visible viewport into the
-    ///     <see cref="View"/>.
-    /// </param>
-    public DrawEventArgs (Rectangle newViewport, Rectangle oldViewport)
-    {
-        NewViewport = newViewport;
-        OldViewport = oldViewport;
-    }
-
-    /// <summary>If set to true, the draw operation will be canceled, if applicable.</summary>
-    public bool Cancel { get; set; }
-
-    /// <summary>Gets the Content-relative rectangle describing the old visible viewport into the <see cref="View"/>.</summary>
-    public Rectangle OldViewport { get; }
-
-    /// <summary>Gets the Content-relative rectangle describing the currently visible viewport into the <see cref="View"/>.</summary>
-    public Rectangle NewViewport { get; }
-}
-
-/// <summary>Defines the event arguments for <see cref="View.SetFocus()"/></summary>
-public class FocusEventArgs : EventArgs
-{
-    /// <summary>Constructs.</summary>
-    /// <param name="leaving">The view that is losing focus.</param>
-    /// <param name="entering">The view that is gaining focus.</param>
-    public FocusEventArgs (View leaving, View entering) {
-        Leaving = leaving;
-        Entering = entering;
-    }
-
-    /// <summary>
-    ///     Indicates if the current focus event has already been processed and the driver should stop notifying any other
-    ///     event subscriber. It's important to set this value to true specially when updating any View's layout from inside the
-    ///     subscriber method.
-    /// </summary>
-    public bool Handled { get; set; }
-
-    /// <summary>Indicates the view that is losing focus.</summary>
-    public View Leaving { get; set; }
-
-    /// <summary>Indicates the view that is gaining focus.</summary>
-    public View Entering { get; set; }
-
-}
+}
\ No newline at end of file
diff --git a/Terminal.Gui/View/ViewSubViews.cs b/Terminal.Gui/View/ViewSubViews.cs
deleted file mode 100644
index 79cca431e..000000000
--- a/Terminal.Gui/View/ViewSubViews.cs
+++ /dev/null
@@ -1,948 +0,0 @@
-using System.Diagnostics;
-
-namespace Terminal.Gui;
-
-public partial class View
-{
-    private static readonly IList<View> _empty = new List<View> (0).AsReadOnly ();
-    internal bool _addingView;
-    private List<View> _subviews; // This is null, and allocated on demand.
-    private View _superView;
-
-    /// <summary>Indicates whether the view was added to <see cref="SuperView"/>.</summary>
-    public bool IsAdded { get; private set; }
-
-    /// <summary>Returns a value indicating if this View is currently on Top (Active)</summary>
-    public bool IsCurrentTop => Application.Current == this;
-
-    /// <summary>This returns a list of the subviews contained by this view.</summary>
-    /// <value>The subviews.</value>
-    public IList<View> Subviews => _subviews?.AsReadOnly () ?? _empty;
-
-    /// <summary>Returns the container for this view, or null if this view has not been added to a container.</summary>
-    /// <value>The super view.</value>
-    public virtual View SuperView
-    {
-        get => _superView;
-        set => throw new NotImplementedException ();
-    }
-
-    // Internally, we use InternalSubviews rather than subviews, as we do not expect us
-    // to make the same mistakes our users make when they poke at the Subviews.
-    internal IList<View> InternalSubviews => _subviews ?? _empty;
-
-    /// <summary>Adds a subview (child) to this view.</summary>
-    /// <remarks>
-    ///     <para>
-    ///         The Views that have been added to this view can be retrieved via the <see cref="Subviews"/> property. See also
-    ///         <seealso cref="Remove(View)"/> <seealso cref="RemoveAll"/>
-    ///     </para>
-    ///     <para>
-    ///         Subviews will be disposed when this View is disposed. In other-words, calling this method causes
-    ///         the lifecycle of the subviews to be transferred to this View.
-    ///     </para>
-    /// </remarks>
-    /// <param name="view">The view to add.</param>
-    /// <returns>The view that was added.</returns>
-    public virtual View Add (View view)
-    {
-        if (view is null)
-        {
-            return view;
-        }
-
-        if (_subviews is null)
-        {
-            _subviews = new ();
-        }
-
-        if (_tabIndexes is null)
-        {
-            _tabIndexes = new ();
-        }
-
-        _subviews.Add (view);
-        _tabIndexes.Add (view);
-        view._superView = this;
-
-        if (view.CanFocus)
-        {
-            _addingView = true;
-
-            if (SuperView?.CanFocus == false)
-            {
-                SuperView._addingView = true;
-                SuperView.CanFocus = true;
-                SuperView._addingView = false;
-            }
-
-            // QUESTION: This automatic behavior of setting CanFocus to true on the SuperView is not documented, and is annoying.
-            CanFocus = true;
-            view._tabIndex = _tabIndexes.IndexOf (view);
-            _addingView = false;
-        }
-
-        if (view.Enabled && !Enabled)
-        {
-            view._oldEnabled = true;
-            view.Enabled = false;
-        }
-
-        OnAdded (new (this, view));
-
-        if (IsInitialized && !view.IsInitialized)
-        {
-            view.BeginInit ();
-            view.EndInit ();
-        }
-
-        CheckDimAuto ();
-        SetNeedsLayout ();
-        SetNeedsDisplay ();
-
-        return view;
-    }
-
-    /// <summary>Adds the specified views (children) to the view.</summary>
-    /// <param name="views">Array of one or more views (can be optional parameter).</param>
-    /// <remarks>
-    ///     <para>
-    ///         The Views that have been added to this view can be retrieved via the <see cref="Subviews"/> property. See also
-    ///         <seealso cref="Remove(View)"/> and <seealso cref="RemoveAll"/>.
-    ///     </para>
-    ///     <para>
-    ///         Subviews will be disposed when this View is disposed. In other-words, calling this method causes
-    ///         the lifecycle of the subviews to be transferred to this View.
-    ///     </para>
-    /// </remarks>
-    public void Add (params View [] views)
-    {
-        if (views is null)
-        {
-            return;
-        }
-
-        foreach (View view in views)
-        {
-            Add (view);
-        }
-    }
-
-    /// <summary>Event fired when this view is added to another.</summary>
-    public event EventHandler<SuperViewChangedEventArgs> Added;
-
-    /// <summary>Moves the subview backwards in the hierarchy, only one step</summary>
-    /// <param name="subview">The subview to send backwards</param>
-    /// <remarks>If you want to send the view all the way to the back use SendSubviewToBack.</remarks>
-    public void BringSubviewForward (View subview)
-    {
-        PerformActionForSubview (
-                                 subview,
-                                 x =>
-                                 {
-                                     int idx = _subviews.IndexOf (x);
-
-                                     if (idx + 1 < _subviews.Count)
-                                     {
-                                         _subviews.Remove (x);
-                                         _subviews.Insert (idx + 1, x);
-                                     }
-                                 }
-                                );
-    }
-
-    /// <summary>Brings the specified subview to the front so it is drawn on top of any other views.</summary>
-    /// <param name="subview">The subview to send to the front</param>
-    /// <remarks><seealso cref="SendSubviewToBack"/>.</remarks>
-    public void BringSubviewToFront (View subview)
-    {
-        PerformActionForSubview (
-                                 subview,
-                                 x =>
-                                 {
-                                     _subviews.Remove (x);
-                                     _subviews.Add (x);
-                                 }
-                                );
-    }
-
-    /// <summary>Get the top superview of a given <see cref="View"/>.</summary>
-    /// <returns>The superview view.</returns>
-    public View GetTopSuperView (View view = null, View superview = null)
-    {
-        View top = superview ?? Application.Top;
-
-        for (View v = view?.SuperView ?? this?.SuperView; v != null; v = v.SuperView)
-        {
-            top = v;
-
-            if (top == superview)
-            {
-                break;
-            }
-        }
-
-        return top;
-    }
-
-    /// <summary>Method invoked when a subview is being added to this view.</summary>
-    /// <param name="e">Event where <see cref="ViewEventArgs.View"/> is the subview being added.</param>
-    public virtual void OnAdded (SuperViewChangedEventArgs e)
-    {
-        View view = e.Child;
-        view.IsAdded = true;
-        view.OnResizeNeeded ();
-        view.Added?.Invoke (this, e);
-    }
-
-    /// <summary>Method invoked when a subview is being removed from this view.</summary>
-    /// <param name="e">Event args describing the subview being removed.</param>
-    public virtual void OnRemoved (SuperViewChangedEventArgs e)
-    {
-        View view = e.Child;
-        view.IsAdded = false;
-        view.Removed?.Invoke (this, e);
-    }
-
-    /// <summary>Removes a subview added via <see cref="Add(View)"/> or <see cref="Add(View[])"/> from this View.</summary>
-    /// <remarks>
-    ///     <para>
-    ///         Normally Subviews will be disposed when this View is disposed. Removing a Subview causes ownership of the
-    ///         Subview's
-    ///         lifecycle to be transferred to the caller; the caller muse call <see cref="Dispose"/>.
-    ///     </para>
-    /// </remarks>
-    public virtual View Remove (View view)
-    {
-        if (view is null || _subviews is null)
-        {
-            return view;
-        }
-
-        Rectangle touched = view.Frame;
-        _subviews.Remove (view);
-        _tabIndexes.Remove (view);
-        view._superView = null;
-        view._tabIndex = -1;
-        SetNeedsLayout ();
-        SetNeedsDisplay ();
-
-        foreach (View v in _subviews)
-        {
-            if (v.Frame.IntersectsWith (touched))
-            {
-                view.SetNeedsDisplay ();
-            }
-        }
-
-        OnRemoved (new (this, view));
-
-        if (Focused == view)
-        {
-            Focused = null;
-        }
-
-        return view;
-    }
-
-    /// <summary>
-    ///     Removes all subviews (children) added via <see cref="Add(View)"/> or <see cref="Add(View[])"/> from this View.
-    /// </summary>
-    /// <remarks>
-    ///     <para>
-    ///         Normally Subviews will be disposed when this View is disposed. Removing a Subview causes ownership of the
-    ///         Subview's
-    ///         lifecycle to be transferred to the caller; the caller must call <see cref="Dispose"/> on any Views that were
-    ///         added.
-    ///     </para>
-    /// </remarks>
-    public virtual void RemoveAll ()
-    {
-        if (_subviews is null)
-        {
-            return;
-        }
-
-        while (_subviews.Count > 0)
-        {
-            Remove (_subviews [0]);
-        }
-    }
-
-    /// <summary>Event fired when this view is removed from another.</summary>
-    public event EventHandler<SuperViewChangedEventArgs> Removed;
-
-    /// <summary>Moves the subview backwards in the hierarchy, only one step</summary>
-    /// <param name="subview">The subview to send backwards</param>
-    /// <remarks>If you want to send the view all the way to the back use SendSubviewToBack.</remarks>
-    public void SendSubviewBackwards (View subview)
-    {
-        PerformActionForSubview (
-                                 subview,
-                                 x =>
-                                 {
-                                     int idx = _subviews.IndexOf (x);
-
-                                     if (idx > 0)
-                                     {
-                                         _subviews.Remove (x);
-                                         _subviews.Insert (idx - 1, x);
-                                     }
-                                 }
-                                );
-    }
-
-    /// <summary>Sends the specified subview to the front so it is the first view drawn</summary>
-    /// <param name="subview">The subview to send to the front</param>
-    /// <remarks><seealso cref="BringSubviewToFront(View)"/>.</remarks>
-    public void SendSubviewToBack (View subview)
-    {
-        PerformActionForSubview (
-                                 subview,
-                                 x =>
-                                 {
-                                     _subviews.Remove (x);
-                                     _subviews.Insert (0, subview);
-                                 }
-                                );
-    }
-
-    private void PerformActionForSubview (View subview, Action<View> action)
-    {
-        if (_subviews.Contains (subview))
-        {
-            action (subview);
-        }
-
-        SetNeedsDisplay ();
-        subview.SetNeedsDisplay ();
-    }
-
-    #region Focus
-
-    /// <summary>Exposed as `internal` for unit tests. Indicates focus navigation direction.</summary>
-    internal enum NavigationDirection
-    {
-        /// <summary>Navigate forward.</summary>
-        Forward,
-
-        /// <summary>Navigate backwards.</summary>
-        Backward
-    }
-
-    /// <summary>Event fired when the view gets focus.</summary>
-    public event EventHandler<FocusEventArgs> Enter;
-
-    /// <summary>Event fired when the view looses focus.</summary>
-    public event EventHandler<FocusEventArgs> Leave;
-
-    private NavigationDirection _focusDirection;
-
-    internal NavigationDirection FocusDirection
-    {
-        get => SuperView?.FocusDirection ?? _focusDirection;
-        set
-        {
-            if (SuperView is { })
-            {
-                SuperView.FocusDirection = value;
-            }
-            else
-            {
-                _focusDirection = value;
-            }
-        }
-    }
-
-    private bool _hasFocus;
-
-    /// <inheritdoc/>
-    public bool HasFocus
-    {
-        set => SetHasFocus (value, this, true);
-        get => _hasFocus;
-    }
-
-    private void SetHasFocus (bool value, View view, bool force = false)
-    {
-        if (HasFocus != value || force)
-        {
-            _hasFocus = value;
-
-            if (value)
-            {
-                OnEnter (view);
-            }
-            else
-            {
-                OnLeave (view);
-            }
-
-            SetNeedsDisplay ();
-        }
-
-        // Remove focus down the chain of subviews if focus is removed
-        if (!value && Focused is { })
-        {
-            View f = Focused;
-            f.OnLeave (view);
-            f.SetHasFocus (false, view);
-            Focused = null;
-        }
-    }
-
-    /// <summary>Event fired when the <see cref="CanFocus"/> value is being changed.</summary>
-    public event EventHandler CanFocusChanged;
-
-    /// <summary>Method invoked when the <see cref="CanFocus"/> property from a view is changed.</summary>
-    public virtual void OnCanFocusChanged () { CanFocusChanged?.Invoke (this, EventArgs.Empty); }
-
-    private bool _oldCanFocus;
-    private bool _canFocus;
-
-    /// <summary>Gets or sets a value indicating whether this <see cref="View"/> can focus.</summary>
-    public bool CanFocus
-    {
-        get => _canFocus;
-        set
-        {
-            if (!_addingView && IsInitialized && SuperView?.CanFocus == false && value)
-            {
-                throw new InvalidOperationException ("Cannot set CanFocus to true if the SuperView CanFocus is false!");
-            }
-
-            if (_canFocus == value)
-            {
-                return;
-            }
-
-            _canFocus = value;
-
-            switch (_canFocus)
-            {
-                case false when _tabIndex > -1:
-                    TabIndex = -1;
-
-                    break;
-                case true when SuperView?.CanFocus == false && _addingView:
-                    SuperView.CanFocus = true;
-
-                    break;
-            }
-
-            if (_canFocus && _tabIndex == -1)
-            {
-                TabIndex = SuperView is { } ? SuperView._tabIndexes.IndexOf (this) : -1;
-            }
-
-            TabStop = _canFocus;
-
-            if (!_canFocus && SuperView?.Focused == this)
-            {
-                SuperView.Focused = null;
-            }
-
-            if (!_canFocus && HasFocus)
-            {
-                SetHasFocus (false, this);
-                SuperView?.EnsureFocus ();
-
-                if (SuperView is { Focused: null })
-                {
-                    SuperView.FocusNext ();
-
-                    if (SuperView.Focused is null && Application.Current is { })
-                    {
-                        Application.Current.FocusNext ();
-                    }
-
-                    ApplicationOverlapped.BringOverlappedTopToFront ();
-                }
-            }
-
-            if (_subviews is { } && IsInitialized)
-            {
-                foreach (View view in _subviews)
-                {
-                    if (view.CanFocus != value)
-                    {
-                        if (!value)
-                        {
-                            view._oldCanFocus = view.CanFocus;
-                            view._oldTabIndex = view._tabIndex;
-                            view.CanFocus = false;
-                            view._tabIndex = -1;
-                        }
-                        else
-                        {
-                            if (_addingView)
-                            {
-                                view._addingView = true;
-                            }
-
-                            view.CanFocus = view._oldCanFocus;
-                            view._tabIndex = view._oldTabIndex;
-                            view._addingView = false;
-                        }
-                    }
-                }
-
-                if (this is Toplevel && Application.Current.Focused != this)
-                {
-                    ApplicationOverlapped.BringOverlappedTopToFront ();
-                }
-            }
-
-            OnCanFocusChanged ();
-            SetNeedsDisplay ();
-        }
-    }
-
-    /// <summary>
-    /// Called when a view gets focus.
-    /// </summary>
-    /// <param name="view">The view that is losing focus.</param>
-    /// <returns><c>true</c>, if the event was handled, <c>false</c> otherwise.</returns>
-    public virtual bool OnEnter (View view)
-    {
-        var args = new FocusEventArgs (view, this);
-        Enter?.Invoke (this, args);
-
-        if (args.Handled)
-        {
-            return true;
-        }
-
-        return false;
-    }
-
-    /// <summary>Method invoked when a view loses focus.</summary>
-    /// <param name="view">The view that is getting focus.</param>
-    /// <returns><c>true</c>, if the event was handled, <c>false</c> otherwise.</returns>
-    public virtual bool OnLeave (View view)
-    {
-        var args = new FocusEventArgs (this, view);
-        Leave?.Invoke (this, args);
-
-        if (args.Handled)
-        {
-            return true;
-        }
-
-        return false;
-    }
-
-    // BUGBUG: This API is poorly defined and implemented. It does not specify what it means if THIS view is focused and has no subviews.
-    /// <summary>Returns the currently focused Subview inside this view, or null if nothing is focused.</summary>
-    /// <value>The focused.</value>
-    public View Focused { get; private set; }
-
-    // BUGBUG: This API is poorly defined and implemented. It does not specify what it means if THIS view is focused and has no subviews.
-    /// <summary>Returns the most focused Subview in the chain of subviews (the leaf view that has the focus).</summary>
-    /// <value>The most focused View.</value>
-    public View MostFocused
-    {
-        get
-        {
-            if (Focused is null)
-            {
-                return null;
-            }
-
-            View most = Focused.MostFocused;
-
-            if (most is { })
-            {
-                return most;
-            }
-
-            return Focused;
-        }
-    }
-
-    /// <summary>Causes the specified subview to have focus.</summary>
-    /// <param name="view">View.</param>
-    private void SetFocus (View view)
-    {
-        if (view is null)
-        {
-            return;
-        }
-
-        //Console.WriteLine ($"Request to focus {view}");
-        if (!view.CanFocus || !view.Visible || !view.Enabled)
-        {
-            return;
-        }
-
-        if (Focused?._hasFocus == true && Focused == view)
-        {
-            return;
-        }
-
-        if ((Focused?._hasFocus == true && Focused?.SuperView == view) || view == this)
-        {
-            if (!view._hasFocus)
-            {
-                view._hasFocus = true;
-            }
-
-            return;
-        }
-
-        // Make sure that this view is a subview
-        View c;
-
-        for (c = view._superView; c != null; c = c._superView)
-        {
-            if (c == this)
-            {
-                break;
-            }
-        }
-
-        if (c is null)
-        {
-            throw new ArgumentException ("the specified view is not part of the hierarchy of this view");
-        }
-
-        if (Focused is { })
-        {
-            Focused.SetHasFocus (false, view);
-        }
-
-        View f = Focused;
-        Focused = view;
-        Focused.SetHasFocus (true, f);
-        Focused.EnsureFocus ();
-
-        // Send focus upwards
-        if (SuperView is { })
-        {
-            SuperView.SetFocus (this);
-        }
-        else
-        {
-            SetFocus (this);
-        }
-    }
-
-    /// <summary>Causes this view to be focused and entire Superview hierarchy to have the focused order updated.</summary>
-    public void SetFocus ()
-    {
-        if (!CanBeVisible (this) || !Enabled)
-        {
-            if (HasFocus)
-            {
-                SetHasFocus (false, this);
-            }
-
-            return;
-        }
-
-        if (SuperView is { })
-        {
-            SuperView.SetFocus (this);
-        }
-        else
-        {
-            SetFocus (this);
-        }
-    }
-
-    /// <summary>
-    ///     If there is no focused subview, calls <see cref="FocusFirst"/> or <see cref="FocusLast"/> based on <see cref="FocusDirection"/>. 
-    ///     does nothing.
-    /// </summary>
-    public void EnsureFocus ()
-    {
-        if (Focused is null && _subviews?.Count > 0)
-        {
-            if (FocusDirection == NavigationDirection.Forward)
-            {
-                FocusFirst ();
-            }
-            else
-            {
-                FocusLast ();
-            }
-        }
-    }
-
-    /// <summary>
-    ///     Focuses the last focusable view in <see cref="View.TabIndexes"/> if one exists. If there are no views in <see cref="View.TabIndexes"/> then the focus is set to the view itself.
-    /// </summary>
-    public void FocusFirst (bool overlapped = false)
-    {
-        if (!CanBeVisible (this))
-        {
-            return;
-        }
-
-        if (_tabIndexes is null)
-        {
-            SuperView?.SetFocus (this);
-
-            return;
-        }
-
-        foreach (View view in _tabIndexes.Where (v => !overlapped || v.Arrangement.HasFlag (ViewArrangement.Overlapped)))
-        {
-            if (view.CanFocus && view._tabStop && view.Visible && view.Enabled)
-            {
-                SetFocus (view);
-
-                return;
-            }
-        }
-    }
-
-    /// <summary>
-    ///     Focuses the last focusable view in <see cref="View.TabIndexes"/> if one exists. If there are no views in <see cref="View.TabIndexes"/> then the focus is set to the view itself.
-    /// </summary>
-    public void FocusLast (bool overlapped = false)
-    {
-        if (!CanBeVisible (this))
-        {
-            return;
-        }
-
-        if (_tabIndexes is null)
-        {
-            SuperView?.SetFocus (this);
-
-            return;
-        }
-
-        foreach (View view in _tabIndexes.Where (v => !overlapped || v.Arrangement.HasFlag (ViewArrangement.Overlapped)).Reverse ())
-        {
-            if (view.CanFocus && view._tabStop && view.Visible && view.Enabled)
-            {
-                SetFocus (view);
-
-                return;
-            }
-        }
-    }
-
-    /// <summary>
-    ///     Focuses the previous view in <see cref="View.TabIndexes"/>. If there is no previous view, the focus is set to the view itself.
-    /// </summary>
-    /// <returns><see langword="true"/> if previous was focused, <see langword="false"/> otherwise.</returns>
-    public bool FocusPrev ()
-    {
-        if (!CanBeVisible (this))
-        {
-            return false;
-        }
-
-        FocusDirection = NavigationDirection.Backward;
-
-        if (TabIndexes is null || TabIndexes.Count == 0)
-        {
-            return false;
-        }
-
-        if (Focused is null)
-        {
-            FocusLast ();
-
-            return Focused != null;
-        }
-
-        int focusedIdx = -1;
-
-        for (int i = TabIndexes.Count; i > 0;)
-        {
-            i--;
-            View w = TabIndexes [i];
-
-            if (w.HasFocus)
-            {
-                if (w.FocusPrev ())
-                {
-                    return true;
-                }
-
-                focusedIdx = i;
-
-                continue;
-            }
-
-            if (w.CanFocus && focusedIdx != -1 && w._tabStop && w.Visible && w.Enabled)
-            {
-                Focused.SetHasFocus (false, w);
-
-                // If the focused view is overlapped don't focus on the next if it's not overlapped.
-                if (Focused.Arrangement.HasFlag (ViewArrangement.Overlapped) && !w.Arrangement.HasFlag (ViewArrangement.Overlapped))
-                {
-                    return false;
-                }
-
-                // If the focused view is not overlapped and the next is, skip it
-                if (!Focused.Arrangement.HasFlag (ViewArrangement.Overlapped) && w.Arrangement.HasFlag (ViewArrangement.Overlapped))
-                {
-                   continue;
-                }
-
-                if (w.CanFocus && w._tabStop && w.Visible && w.Enabled)
-                {
-                    w.FocusLast ();
-                }
-
-                SetFocus (w);
-
-                return true;
-            }
-        }
-
-        // There's no prev view in tab indexes.
-        if (Focused is { })
-        {
-            // Leave Focused
-            Focused.SetHasFocus (false, this);
-
-            if (Focused.Arrangement.HasFlag (ViewArrangement.Overlapped))
-            {
-                FocusLast (true);
-                return true;
-            }
-
-            // Signal to caller no next view was found
-            Focused = null;
-        }
-
-        return false;
-    }
-
-    /// <summary>
-    ///     Focuses the next view in <see cref="View.TabIndexes"/>. If there is no next view, the focus is set to the view itself.
-    /// </summary>
-    /// <returns><see langword="true"/> if next was focused, <see langword="false"/> otherwise.</returns>
-    public bool FocusNext ()
-    {
-        if (!CanBeVisible (this))
-        {
-            return false;
-        }
-
-        FocusDirection = NavigationDirection.Forward;
-
-        if (TabIndexes is null || TabIndexes.Count == 0)
-        {
-            return false;
-        }
-
-        if (Focused is null)
-        {
-            FocusFirst ();
-
-            return Focused != null;
-        }
-
-        int focusedIdx = -1;
-
-        for (var i = 0; i < TabIndexes.Count; i++)
-        {
-            View w = TabIndexes [i];
-
-            if (w.HasFocus)
-            {
-                if (w.FocusNext ())
-                {
-                    return true;
-                }
-
-                focusedIdx = i;
-
-                continue;
-            }
-
-            if (w.CanFocus && focusedIdx != -1 && w._tabStop && w.Visible && w.Enabled)
-            {
-                Focused.SetHasFocus (false, w);
-
-                // If the focused view is overlapped don't focus on the next if it's not overlapped.
-                if (Focused.Arrangement.HasFlag (ViewArrangement.Overlapped) && !w.Arrangement.HasFlag (ViewArrangement.Overlapped))
-                {
-                    return false;
-                }
-
-                // If the focused view is not overlapped and the next is, skip it
-                if (!Focused.Arrangement.HasFlag (ViewArrangement.Overlapped) && w.Arrangement.HasFlag (ViewArrangement.Overlapped))
-                {
-                    continue;
-                }
-
-                if (w.CanFocus && w._tabStop && w.Visible && w.Enabled)
-                {
-                    w.FocusFirst ();
-                }
-
-                SetFocus (w);
-
-                return true;
-            }
-        }
-
-        // There's no next view in tab indexes.
-        if (Focused is { })
-        {
-            // Leave Focused
-            Focused.SetHasFocus (false, this);
-
-            if (Focused.Arrangement.HasFlag (ViewArrangement.Overlapped))
-            {
-                FocusFirst (true);
-                return true;
-            }
-
-            // Signal to caller no next view was found
-            Focused = null;
-        }
-
-        return false;
-    }
-
-    private View GetMostFocused (View view)
-    {
-        if (view is null)
-        {
-            return null;
-        }
-
-        return view.Focused is { } ? GetMostFocused (view.Focused) : view;
-    }
-
-    /// <summary>
-    /// Gets or sets the cursor style to be used when the view is focused. The default is <see cref="CursorVisibility.Invisible"/>.
-    /// </summary>
-    public CursorVisibility CursorVisibility { get; set; } = CursorVisibility.Invisible;
-
-    /// <summary>
-    ///     Positions the cursor in the right position based on the currently focused view in the chain.
-    /// </summary>
-    /// <remarks>
-    ///     <para>
-    ///         Views that are focusable should override <see cref="PositionCursor"/> to make sure that the cursor is
-    ///         placed in a location that makes sense. Some terminals do not have a way of hiding the cursor, so it can be
-    ///         distracting to have the cursor left at the last focused view. So views should make sure that they place the
-    ///         cursor in a visually sensible place. The default implementation of <see cref="PositionCursor"/> will place the
-    ///         cursor at either the hotkey (if defined) or <c>0,0</c>.
-    ///     </para>
-    /// </remarks>
-    /// <returns>Viewport-relative cursor position. Return <see langword="null"/> to ensure the cursor is not visible.</returns>
-    public virtual Point? PositionCursor ()
-    {
-        if (IsInitialized && CanFocus && HasFocus)
-        {
-            // By default, position the cursor at the hotkey (if any) or 0, 0.
-            Move (TextFormatter.HotKeyPos == -1 ? 0 : TextFormatter.CursorPosition, 0);
-        }
-
-        // Returning null will hide the cursor.
-        return null;
-    }
-
-    #endregion Focus
-}
diff --git a/UICatalog/Scenarios/ViewExperiments.cs b/UICatalog/Scenarios/ViewExperiments.cs
index 263a507d9..4c212b8b7 100644
--- a/UICatalog/Scenarios/ViewExperiments.cs
+++ b/UICatalog/Scenarios/ViewExperiments.cs
@@ -27,6 +27,8 @@ public class ViewExperiments : Scenario
             Title = "View1",
             ColorScheme = Colors.ColorSchemes ["Base"],
             Id = "View1",
+            ShadowStyle = ShadowStyle.Transparent,
+            BorderStyle = LineStyle.Double,
             CanFocus = true, // Can't drag without this? BUGBUG
             Arrangement = ViewArrangement.Movable | ViewArrangement.Overlapped
         };
@@ -46,16 +48,7 @@ public class ViewExperiments : Scenario
 
         //app.Add (view);
 
-        view.Margin.Thickness = new (0);
-        view.Margin.ColorScheme = Colors.ColorSchemes ["Toplevel"];
-        view.Margin.Data = "Margin";
-        view.Border.Thickness = new (1);
-        view.Border.LineStyle = LineStyle.Double;
-        view.Border.ColorScheme = view.ColorScheme;
-        view.Border.Data = "Border";
-        view.Padding.Thickness = new (0);
-        view.Padding.ColorScheme = Colors.ColorSchemes ["Error"];
-        view.Padding.Data = "Padding";
+        view.BorderStyle = LineStyle.Double;
 
         var view2 = new View
         {
@@ -66,6 +59,8 @@ public class ViewExperiments : Scenario
             Title = "View2",
             ColorScheme = Colors.ColorSchemes ["Base"],
             Id = "View2",
+            ShadowStyle = ShadowStyle.Transparent,
+            BorderStyle = LineStyle.Double,
             CanFocus = true, // Can't drag without this? BUGBUG
             Arrangement = ViewArrangement.Movable | ViewArrangement.Overlapped
         };
@@ -85,16 +80,6 @@ public class ViewExperiments : Scenario
         view2.Add (button);
 
         view2.Add (button);
-        view2.Margin.Thickness = new (0);
-        view2.Margin.ColorScheme = Colors.ColorSchemes ["Toplevel"];
-        view2.Margin.Data = "Margin";
-        view2.Border.Thickness = new (1);
-        view2.Border.LineStyle = LineStyle.Double;
-        view2.Border.ColorScheme = view2.ColorScheme;
-        view2.Border.Data = "Border";
-        view2.Padding.Thickness = new (0);
-        view2.Padding.ColorScheme = Colors.ColorSchemes ["Error"];
-        view2.Padding.Data = "Padding";
 
         button = new ()
         {

From 9b89fe6466576ba58cbb26a96bd1eb10ef72c98a Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Thu, 25 Jul 2024 11:21:49 -0600
Subject: [PATCH 31/33] Code cleanup and API docs - getting better
 understanding of navigation code.

---
 Terminal.Gui/View/View.Hierarchy.cs  | 10 ++--
 Terminal.Gui/View/View.Navigation.cs | 86 +++++++++++++++++++---------
 Terminal.Gui/View/View.cs            |  2 +-
 UICatalog/Scenarios/Notepad.cs       |  1 -
 4 files changed, 64 insertions(+), 35 deletions(-)

diff --git a/Terminal.Gui/View/View.Hierarchy.cs b/Terminal.Gui/View/View.Hierarchy.cs
index 125baf33f..d66253849 100644
--- a/Terminal.Gui/View/View.Hierarchy.cs
+++ b/Terminal.Gui/View/View.Hierarchy.cs
@@ -3,7 +3,6 @@ namespace Terminal.Gui;
 public partial class View // SuperView/SubView hierarchy management (SuperView, SubViews, Add, Remove, etc.)
 {
     private static readonly IList<View> _empty = new List<View> (0).AsReadOnly ();
-    internal bool _addingView;
     private List<View> _subviews; // This is null, and allocated on demand.
     private View _superView;
 
@@ -62,19 +61,20 @@ public partial class View // SuperView/SubView hierarchy management (SuperView,
 
         if (view.CanFocus)
         {
-            _addingView = true;
+            // BUGBUG: This is a poor API design. Automatic behavior like this is non-obvious and should be avoided. Instead, callers to Add should be explicit about what they want.
+            _addingViewSoCanFocusAlsoUpdatesSuperView = true;
 
             if (SuperView?.CanFocus == false)
             {
-                SuperView._addingView = true;
+                SuperView._addingViewSoCanFocusAlsoUpdatesSuperView = true;
                 SuperView.CanFocus = true;
-                SuperView._addingView = false;
+                SuperView._addingViewSoCanFocusAlsoUpdatesSuperView = false;
             }
 
             // QUESTION: This automatic behavior of setting CanFocus to true on the SuperView is not documented, and is annoying.
             CanFocus = true;
             view._tabIndex = _tabIndexes.IndexOf (view);
-            _addingView = false;
+            _addingViewSoCanFocusAlsoUpdatesSuperView = false;
         }
 
         if (view.Enabled && !Enabled)
diff --git a/Terminal.Gui/View/View.Navigation.cs b/Terminal.Gui/View/View.Navigation.cs
index 4ff99c3d7..3cc0c1f11 100644
--- a/Terminal.Gui/View/View.Navigation.cs
+++ b/Terminal.Gui/View/View.Navigation.cs
@@ -75,7 +75,7 @@ public partial class View // Focus and cross-view navigation management (TabStop
     private NavigationDirection _focusDirection;
 
     /// <summary>
-    ///     Gets or sets the focus direction for this view and all subviews.
+    ///     INTERNAL API that gets or sets the focus direction for this view and all subviews.
     ///     Setting this property will set the focus direction for all views up the SuperView hierarchy.
     /// </summary>
     internal NavigationDirection FocusDirection
@@ -160,19 +160,14 @@ public partial class View // Focus and cross-view navigation management (TabStop
         }
     }
 
-    /// <summary>Raised when <see cref="CanFocus"/> has been changed.</summary>
-    /// <remarks>
-    ///     Raised by the <see cref="OnCanFocusChanged"/> virtual method.
-    /// </remarks>
-    public event EventHandler CanFocusChanged;
-
-    /// <summary>Invoked when the <see cref="CanFocus"/> property from a view is changed.</summary>
-    /// <remarks>
-    ///     Raises the <see cref="CanFocusChanged"/> event.
-    /// </remarks>
-    public virtual void OnCanFocusChanged () { CanFocusChanged?.Invoke (this, EventArgs.Empty); }
+    // BUGBUG: This is a poor API design. Automatic behavior like this is non-obvious and should be avoided. Instead, callers to Add should be explicit about what they want.
+    // Set to true in Add() to indicate that the view being added to a SuperView has CanFocus=true.
+    // Makes it so CanFocus will update the SuperView's CanFocus property.
+    internal bool _addingViewSoCanFocusAlsoUpdatesSuperView;
 
+    // Used to cache CanFocus on subviews when CanFocus is set to false so that it can be restored when CanFocus is changed back to true
     private bool _oldCanFocus;
+
     private bool _canFocus;
 
     /// <summary>Gets or sets a value indicating whether this <see cref="View"/> can be focused.</summary>
@@ -180,13 +175,24 @@ public partial class View // Focus and cross-view navigation management (TabStop
     ///     <para>
     ///         <see cref="SuperView"/> must also have <see cref="CanFocus"/> set to <see langword="true"/>.
     ///     </para>
+    ///     <para>
+    ///         When set to <see langword="false"/>, if this view is focused, the focus will be set to the next focusable view.
+    ///     </para>
+    ///     <para>
+    ///         When set to <see langword="false"/>, the <see cref="TabIndex"/> will be set to -1.
+    ///     </para>
+    ///     <para>
+    ///         When set to <see langword="false"/>, the values of <see cref="CanFocus"/> and <see cref="TabIndex"/> for all
+    ///         subviews will be cached so that when <see cref="CanFocus"/> is set back to <see langword="true"/>, the subviews
+    ///         will be restored to their previous values.
+    ///     </para>
     /// </remarks>
     public bool CanFocus
     {
         get => _canFocus;
         set
         {
-            if (!_addingView && IsInitialized && SuperView?.CanFocus == false && value)
+            if (!_addingViewSoCanFocusAlsoUpdatesSuperView && IsInitialized && SuperView?.CanFocus == false && value)
             {
                 throw new InvalidOperationException ("Cannot set CanFocus to true if the SuperView CanFocus is false!");
             }
@@ -204,7 +210,8 @@ public partial class View // Focus and cross-view navigation management (TabStop
                     TabIndex = -1;
 
                     break;
-                case true when SuperView?.CanFocus == false && _addingView:
+
+                case true when SuperView?.CanFocus == false && _addingViewSoCanFocusAlsoUpdatesSuperView:
                     SuperView.CanFocus = true;
 
                     break;
@@ -225,8 +232,9 @@ public partial class View // Focus and cross-view navigation management (TabStop
             if (!_canFocus && HasFocus)
             {
                 SetHasFocus (false, this);
-                SuperView?.EnsureFocus ();
+                SuperView?.FocusFirstOrLast ();
 
+                // If EnsureFocus () didn't set focus to a view, focus the next focusable view in the application
                 if (SuperView is { Focused: null })
                 {
                     SuperView.FocusNext ();
@@ -248,6 +256,7 @@ public partial class View // Focus and cross-view navigation management (TabStop
                     {
                         if (!value)
                         {
+                            // Cache the old CanFocus and TabIndex so that they can be restored when CanFocus is changed back to true
                             view._oldCanFocus = view.CanFocus;
                             view._oldTabIndex = view._tabIndex;
                             view.CanFocus = false;
@@ -255,19 +264,20 @@ public partial class View // Focus and cross-view navigation management (TabStop
                         }
                         else
                         {
-                            if (_addingView)
+                            if (_addingViewSoCanFocusAlsoUpdatesSuperView)
                             {
-                                view._addingView = true;
+                                view._addingViewSoCanFocusAlsoUpdatesSuperView = true;
                             }
 
+                            // Restore the old CanFocus and TabIndex to the values they held before CanFocus was set to false
                             view.CanFocus = view._oldCanFocus;
                             view._tabIndex = view._oldTabIndex;
-                            view._addingView = false;
+                            view._addingViewSoCanFocusAlsoUpdatesSuperView = false;
                         }
                     }
                 }
 
-                if (this is Toplevel && Application.Current.Focused != this)
+                if (this is Toplevel && Application.Current!.Focused != this)
                 {
                     ApplicationOverlapped.BringOverlappedTopToFront ();
                 }
@@ -278,6 +288,18 @@ public partial class View // Focus and cross-view navigation management (TabStop
         }
     }
 
+    /// <summary>Raised when <see cref="CanFocus"/> has been changed.</summary>
+    /// <remarks>
+    ///     Raised by the <see cref="OnCanFocusChanged"/> virtual method.
+    /// </remarks>
+    public event EventHandler CanFocusChanged;
+
+    /// <summary>Invoked when the <see cref="CanFocus"/> property from a view is changed.</summary>
+    /// <remarks>
+    ///     Raises the <see cref="CanFocusChanged"/> event.
+    /// </remarks>
+    public virtual void OnCanFocusChanged () { CanFocusChanged?.Invoke (this, EventArgs.Empty); }
+
     /// <summary>Returns the currently focused Subview inside this view, or <see langword="null"/> if nothing is focused.</summary>
     /// <value>The currently focused Subview.</value>
     public View Focused { get; private set; }
@@ -361,7 +383,7 @@ public partial class View // Focus and cross-view navigation management (TabStop
         View f = Focused;
         Focused = view;
         Focused.SetHasFocus (true, f);
-        Focused.EnsureFocus ();
+        Focused.FocusFirstOrLast ();
 
         // Send focus upwards
         if (SuperView is { })
@@ -398,11 +420,11 @@ public partial class View // Focus and cross-view navigation management (TabStop
     }
 
     /// <summary>
-    ///     If there is no focused subview, calls <see cref="FocusFirst"/> or <see cref="FocusLast"/> based on
+    ///     INTERNAL helper for calling <see cref="FocusFirst"/> or <see cref="FocusLast"/> based on
     ///     <see cref="FocusDirection"/>.
-    ///     does nothing.
+    ///     FocusDirection is not public. This API is thus non-deterministic from a public API perspective.
     /// </summary>
-    public void EnsureFocus ()
+    internal void FocusFirstOrLast ()
     {
         if (Focused is null && _subviews?.Count > 0)
         {
@@ -418,10 +440,14 @@ public partial class View // Focus and cross-view navigation management (TabStop
     }
 
     /// <summary>
-    ///     Focuses the last focusable view in <see cref="View.TabIndexes"/> if one exists. If there are no views in
+    ///     Focuses the first focusable view in <see cref="View.TabIndexes"/> if one exists. If there are no views in
     ///     <see cref="View.TabIndexes"/> then the focus is set to the view itself.
     /// </summary>
-    public void FocusFirst (bool overlapped = false)
+    /// <param name="overlappedOnly">
+    ///     If <see langword="true"/>, only subviews where <see cref="Arrangement"/> has <see cref="ViewArrangement.Overlapped"/> set
+    ///     will be considered.
+    /// </param>
+    public void FocusFirst (bool overlappedOnly = false)
     {
         if (!CanBeVisible (this))
         {
@@ -435,7 +461,7 @@ public partial class View // Focus and cross-view navigation management (TabStop
             return;
         }
 
-        foreach (View view in _tabIndexes.Where (v => !overlapped || v.Arrangement.HasFlag (ViewArrangement.Overlapped)))
+        foreach (View view in _tabIndexes.Where (v => !overlappedOnly || v.Arrangement.HasFlag (ViewArrangement.Overlapped)))
         {
             if (view.CanFocus && view._tabStop && view.Visible && view.Enabled)
             {
@@ -450,7 +476,11 @@ public partial class View // Focus and cross-view navigation management (TabStop
     ///     Focuses the last focusable view in <see cref="View.TabIndexes"/> if one exists. If there are no views in
     ///     <see cref="View.TabIndexes"/> then the focus is set to the view itself.
     /// </summary>
-    public void FocusLast (bool overlapped = false)
+    /// <param name="overlappedOnly">
+    ///     If <see langword="true"/>, only subviews where <see cref="Arrangement"/> has <see cref="ViewArrangement.Overlapped"/> set
+    ///     will be considered.
+    /// </param>
+    public void FocusLast (bool overlappedOnly = false)
     {
         if (!CanBeVisible (this))
         {
@@ -464,7 +494,7 @@ public partial class View // Focus and cross-view navigation management (TabStop
             return;
         }
 
-        foreach (View view in _tabIndexes.Where (v => !overlapped || v.Arrangement.HasFlag (ViewArrangement.Overlapped)).Reverse ())
+        foreach (View view in _tabIndexes.Where (v => !overlappedOnly || v.Arrangement.HasFlag (ViewArrangement.Overlapped)).Reverse ())
         {
             if (view.CanFocus && view._tabStop && view.Visible && view.Enabled)
             {
diff --git a/Terminal.Gui/View/View.cs b/Terminal.Gui/View/View.cs
index d340a5aa4..8eb5a9374 100644
--- a/Terminal.Gui/View/View.cs
+++ b/Terminal.Gui/View/View.cs
@@ -332,7 +332,7 @@ public partial class View : Responder, ISupportInitializeNotification
                 else
                 {
                     view.Enabled = view._oldEnabled;
-                    view._addingView = _enabled;
+                    view._addingViewSoCanFocusAlsoUpdatesSuperView = _enabled;
                 }
             }
         }
diff --git a/UICatalog/Scenarios/Notepad.cs b/UICatalog/Scenarios/Notepad.cs
index dd962bfc1..2dbca0117 100644
--- a/UICatalog/Scenarios/Notepad.cs
+++ b/UICatalog/Scenarios/Notepad.cs
@@ -309,7 +309,6 @@ public class Notepad : Scenario
         tab.CloneTo (newTabView);
         newTile.ContentView.Add (newTabView);
 
-        newTabView.EnsureFocus ();
         newTabView.FocusFirst ();
         newTabView.FocusNext ();
     }

From ccec0eec1191140c945c6419a03e57126793f910 Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Thu, 25 Jul 2024 12:16:10 -0600
Subject: [PATCH 32/33] Documenting focus code

---
 Terminal.Gui/View/View.Navigation.cs    | 21 ++++++++++++++++-----
 Terminal.Gui/Views/Toplevel.cs          |  2 +-
 UnitTests/Views/TextFieldTests.cs       |  6 +++---
 UnitTests/Views/TreeTableSourceTests.cs |  2 +-
 4 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/Terminal.Gui/View/View.Navigation.cs b/Terminal.Gui/View/View.Navigation.cs
index 3cc0c1f11..edbe5eabc 100644
--- a/Terminal.Gui/View/View.Navigation.cs
+++ b/Terminal.Gui/View/View.Navigation.cs
@@ -1,3 +1,5 @@
+using System.Diagnostics;
+
 namespace Terminal.Gui;
 
 public partial class View // Focus and cross-view navigation management (TabStop, TabIndex, etc...)
@@ -603,7 +605,7 @@ public partial class View // Focus and cross-view navigation management (TabStop
     ///     Focuses the next view in <see cref="View.TabIndexes"/>. If there is no next view, the focus is set to the view
     ///     itself.
     /// </summary>
-    /// <returns><see langword="true"/> if next was focused, <see langword="false"/> otherwise.</returns>
+    /// <returns><see langword="true"/> if focus was changed to another subview (or stayed on this one), <see langword="false"/> otherwise.</returns>
     public bool FocusNext ()
     {
         if (!CanBeVisible (this))
@@ -622,7 +624,7 @@ public partial class View // Focus and cross-view navigation management (TabStop
         {
             FocusFirst ();
 
-            return Focused != null;
+            return Focused is { };
         }
 
         int focusedIdx = -1;
@@ -633,18 +635,25 @@ public partial class View // Focus and cross-view navigation management (TabStop
 
             if (w.HasFocus)
             {
+                // A subview has focus, tell *it* to FocusNext
                 if (w.FocusNext ())
                 {
+                    // The subview changed which of it's subviews had focus
                     return true;
                 }
 
+                Debug.Assert (w.HasFocus);
+
+                // The subview has no subviews that can be next. Cache that we found a focused subview.
                 focusedIdx = i;
 
                 continue;
             }
 
-            if (w.CanFocus && focusedIdx != -1 && w._tabStop && w.Visible && w.Enabled)
+            // The subview does not have focus, but at least one other that can. Can this one be focused?
+            if (focusedIdx != -1 && w.CanFocus && w._tabStop && w.Visible && w.Enabled)
             {
+                // Make w Leave
                 Focused.SetHasFocus (false, w);
 
                 //// If the focused view is overlapped don't focus on the next if it's not overlapped.
@@ -659,6 +668,7 @@ public partial class View // Focus and cross-view navigation management (TabStop
                 //    continue;
                 //}
 
+                // QUESTION: Why do we check these again here?
                 if (w.CanFocus && w._tabStop && w.Visible && w.Enabled)
                 {
                     w.FocusFirst ();
@@ -673,7 +683,7 @@ public partial class View // Focus and cross-view navigation management (TabStop
         // There's no next view in tab indexes.
         if (Focused is { })
         {
-            // Leave Focused
+            // Leave
             Focused.SetHasFocus (false, this);
 
             //if (Focused.Arrangement.HasFlag (ViewArrangement.Overlapped))
@@ -682,7 +692,8 @@ public partial class View // Focus and cross-view navigation management (TabStop
             //    return true;
             //}
 
-            // Signal to caller no next view was found
+            // Signal to caller no next view was found; this will enable it to make a peer
+            // or view up the superview hierarchy have focus.
             Focused = null;
         }
 
diff --git a/Terminal.Gui/Views/Toplevel.cs b/Terminal.Gui/Views/Toplevel.cs
index 26fe724c8..435bd6fc7 100644
--- a/Terminal.Gui/Views/Toplevel.cs
+++ b/Terminal.Gui/Views/Toplevel.cs
@@ -430,7 +430,7 @@ public partial class Toplevel : View
         {
             if (Focused is null)
             {
-                EnsureFocus ();
+                FocusFirstOrLast ();
             }
 
             return null;
diff --git a/UnitTests/Views/TextFieldTests.cs b/UnitTests/Views/TextFieldTests.cs
index ed3a35775..4096ee404 100644
--- a/UnitTests/Views/TextFieldTests.cs
+++ b/UnitTests/Views/TextFieldTests.cs
@@ -78,7 +78,7 @@ public class TextFieldTests (ITestOutputHelper output)
     public void Cancel_TextChanging_ThenBackspace ()
     {
         var tf = new TextField ();
-        tf.EnsureFocus ();
+        tf.FocusFirstOrLast ();
         tf.NewKeyDownEvent (Key.A.WithShift);
         Assert.Equal ("A", tf.Text);
 
@@ -929,7 +929,7 @@ public class TextFieldTests (ITestOutputHelper output)
     public void Backspace_From_End ()
     {
         var tf = new TextField { Text = "ABC" };
-        tf.EnsureFocus ();
+        tf.FocusFirstOrLast ();
         Assert.Equal ("ABC", tf.Text);
         tf.BeginInit ();
         tf.EndInit ();
@@ -956,7 +956,7 @@ public class TextFieldTests (ITestOutputHelper output)
     public void Backspace_From_Middle ()
     {
         var tf = new TextField { Text = "ABC" };
-        tf.EnsureFocus ();
+        tf.FocusFirstOrLast ();
         tf.CursorPosition = 2;
         Assert.Equal ("ABC", tf.Text);
 
diff --git a/UnitTests/Views/TreeTableSourceTests.cs b/UnitTests/Views/TreeTableSourceTests.cs
index a1a319b1b..02625b6cf 100644
--- a/UnitTests/Views/TreeTableSourceTests.cs
+++ b/UnitTests/Views/TreeTableSourceTests.cs
@@ -289,7 +289,7 @@ public class TreeTableSourceTests : IDisposable
 
         var top = new Toplevel ();
         top.Add (tableView);
-        top.EnsureFocus ();
+        top.FocusFirstOrLast ();
         Assert.Equal (tableView, top.MostFocused);
 
         return tableView;

From 15e6b4eff2cc759ca9d3c6f36ebb8d95d38c160b Mon Sep 17 00:00:00 2001
From: Tig <tig@users.noreply.github.com>
Date: Thu, 25 Jul 2024 14:40:11 -0600
Subject: [PATCH 33/33] Documenting focus code

---
 Terminal.Gui/View/View.Navigation.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Terminal.Gui/View/View.Navigation.cs b/Terminal.Gui/View/View.Navigation.cs
index edbe5eabc..292cb5c52 100644
--- a/Terminal.Gui/View/View.Navigation.cs
+++ b/Terminal.Gui/View/View.Navigation.cs
@@ -653,7 +653,7 @@ public partial class View // Focus and cross-view navigation management (TabStop
             // The subview does not have focus, but at least one other that can. Can this one be focused?
             if (focusedIdx != -1 && w.CanFocus && w._tabStop && w.Visible && w.Enabled)
             {
-                // Make w Leave
+                // Make Focused Leave
                 Focused.SetHasFocus (false, w);
 
                 //// If the focused view is overlapped don't focus on the next if it's not overlapped.