diff --git a/Terminal.Gui/Application/Application.Initialization.cs b/Terminal.Gui/Application/Application.Initialization.cs
index 94aab2b17..3d47aeb41 100644
--- a/Terminal.Gui/Application/Application.Initialization.cs
+++ b/Terminal.Gui/Application/Application.Initialization.cs
@@ -39,15 +39,6 @@ public static partial class Application // Initialization (Init/Shutdown)
     [RequiresDynamicCode ("AOT")]
     public static void Init (ConsoleDriver? driver = null, string? driverName = null) { InternalInit (driver, driverName); }
 
-    /// <summary>
-    ///     Gets whether the application has been initialized with <see cref="Init"/> and not yet shutdown with <see cref="Shutdown"/>.
-    /// </summary>
-    /// <remarks>
-    /// <para>
-    ///     The <see cref="InitializedChanged"/> event is raised after the <see cref="Init"/> and <see cref="Shutdown"/> methods have been called.
-    /// </para>
-    /// </remarks>
-    public static bool IsInitialized { get; private set; }
     internal static int MainThreadId { get; set; } = -1;
 
     // INTERNAL function for initializing an app with a Toplevel factory object, driver, and mainloop.
@@ -67,12 +58,12 @@ public static partial class Application // Initialization (Init/Shutdown)
         bool calledViaRunT = false
     )
     {
-        if (IsInitialized && driver is null)
+        if (Initialized && driver is null)
         {
             return;
         }
 
-        if (IsInitialized)
+        if (Initialized)
         {
             throw new InvalidOperationException ("Init has already been called and must be bracketed by Shutdown.");
         }
@@ -181,7 +172,7 @@ public static partial class Application // Initialization (Init/Shutdown)
 
         SupportedCultures = GetSupportedCultures ();
         MainThreadId = Thread.CurrentThread.ManagedThreadId;
-        bool init = IsInitialized = true;
+        bool init = Initialized = true;
         InitializedChanged?.Invoke (null, new (init));
     }
 
@@ -223,17 +214,27 @@ public static partial class Application // Initialization (Init/Shutdown)
     {
         // TODO: Throw an exception if Init hasn't been called.
 
-        bool wasInitialized = IsInitialized;
+        bool wasInitialized = Initialized;
         ResetState ();
         PrintJsonErrors ();
 
         if (wasInitialized)
         {
-            bool init = IsInitialized;
+            bool init = Initialized;
             InitializedChanged?.Invoke (null, new (in init));
         }
     }
 
+    /// <summary>
+    ///     Gets whether the application has been initialized with <see cref="Init"/> and not yet shutdown with <see cref="Shutdown"/>.
+    /// </summary>
+    /// <remarks>
+    /// <para>
+    ///     The <see cref="InitializedChanged"/> event is raised after the <see cref="Init"/> and <see cref="Shutdown"/> methods have been called.
+    /// </para>
+    /// </remarks>
+    public static bool Initialized { get; internal set; }
+
     /// <summary>
     ///     This event is raised after the <see cref="Init"/> and <see cref="Shutdown"/> methods have been called.
     /// </summary>
diff --git a/Terminal.Gui/Application/Application.Keyboard.cs b/Terminal.Gui/Application/Application.Keyboard.cs
index c9fa96c63..211c900bc 100644
--- a/Terminal.Gui/Application/Application.Keyboard.cs
+++ b/Terminal.Gui/Application/Application.Keyboard.cs
@@ -120,7 +120,7 @@ public static partial class Application // Keyboard handling
     /// <returns><see langword="true"/> if the key was handled.</returns>
     public static bool RaiseKeyUpEvent (Key key)
     {
-        if (!IsInitialized)
+        if (!Initialized)
         {
             return true;
         }
diff --git a/Terminal.Gui/Application/Application.Run.cs b/Terminal.Gui/Application/Application.Run.cs
index 93b342628..8a4d4de2a 100644
--- a/Terminal.Gui/Application/Application.Run.cs
+++ b/Terminal.Gui/Application/Application.Run.cs
@@ -328,7 +328,7 @@ 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 (!IsInitialized)
+        if (!Initialized)
         {
             // Init() has NOT been called.
             InternalInit (driver, null, true);
@@ -383,7 +383,7 @@ public static partial class Application // Run (Begin, Run, End, Stop)
     {
         ArgumentNullException.ThrowIfNull (view);
 
-        if (IsInitialized)
+        if (Initialized)
         {
             if (Driver is null)
             {
diff --git a/Terminal.Gui/Application/Application.cs b/Terminal.Gui/Application/Application.cs
index 586fd2d01..d9e6c68d9 100644
--- a/Terminal.Gui/Application/Application.cs
+++ b/Terminal.Gui/Application/Application.cs
@@ -196,7 +196,7 @@ public static partial class Application
         NotifyNewRunState = null;
         NotifyStopRunState = null;
         MouseGrabView = null;
-        IsInitialized = false;
+        Initialized = false;
 
         // Mouse
         _lastMousePosition = null;
diff --git a/UICatalog/Scenario.cs b/UICatalog/Scenario.cs
index a4da47d62..a28fd4eaf 100644
--- a/UICatalog/Scenario.cs
+++ b/UICatalog/Scenario.cs
@@ -4,9 +4,6 @@ using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Diagnostics;
 using System.Linq;
-using System.Reflection.Metadata;
-using System.Text;
-using System.Threading;
 using Terminal.Gui;
 
 namespace UICatalog;
diff --git a/UICatalog/Scenarios/AnimationScenario/AnimationScenario.cs b/UICatalog/Scenarios/AnimationScenario/AnimationScenario.cs
index 3df1fc88e..b1f63596a 100644
--- a/UICatalog/Scenarios/AnimationScenario/AnimationScenario.cs
+++ b/UICatalog/Scenarios/AnimationScenario/AnimationScenario.cs
@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 using System.Diagnostics;
 using System.IO;
 using System.Reflection;
@@ -16,7 +17,7 @@ namespace UICatalog.Scenarios;
 [ScenarioCategory ("Drawing")]
 public class AnimationScenario : Scenario
 {
-    private ImageView _imageView;
+    private ImageView? _imageView;
 
     public override void Main ()
     {
@@ -50,11 +51,11 @@ public class AnimationScenario : Scenario
         Application.Run (win);
         win.Dispose ();
         Application.Shutdown ();
-        Debug.Assert (!Application.IsInitialized);
+        Debug.Assert (!Application.Initialized);
     }
 
 
-    private void OnWinOnInitialized (object sender, EventArgs args)
+    private void OnWinOnInitialized (object? sender, EventArgs args)
     {
         DirectoryInfo dir;
 
@@ -81,12 +82,12 @@ public class AnimationScenario : Scenario
             return;
         }
 
-        _imageView.SetImage (Image.Load<Rgba32> (File.ReadAllBytes (f.FullName)));
+        _imageView!.SetImage (Image.Load<Rgba32> (File.ReadAllBytes (f.FullName)));
 
         Task.Run (
                   () =>
                   {
-                      while (Application.IsInitialized)
+                      while (Application.Initialized)
                       {
                           // When updating from a Thread/Task always use Invoke
                           Application.Invoke (
diff --git a/UnitTests/Application/ApplicationTests.cs b/UnitTests/Application/ApplicationTests.cs
index f9ec74a56..2e49d2b51 100644
--- a/UnitTests/Application/ApplicationTests.cs
+++ b/UnitTests/Application/ApplicationTests.cs
@@ -131,7 +131,7 @@ public class ApplicationTests
             Thread.Sleep ((int)timeoutTime / 10);
 
             // Worst case scenario - something went wrong
-            if (Application.IsInitialized && iteration > 25)
+            if (Application.Initialized && iteration > 25)
             {
                 _output.WriteLine ($"Too many iterations ({iteration}): Calling Application.RequestStop.");
                 Application.RequestStop ();
@@ -279,7 +279,7 @@ public class ApplicationTests
         // Set some values
 
         Application.Init (driverName: driverType.Name);
-        Application.IsInitialized = true;
+       // Application.IsInitialized = true;
 
         // Reset
         Application.ResetState ();
@@ -307,7 +307,7 @@ public class ApplicationTests
             Assert.Equal (Key.Esc, Application.QuitKey);
 
             // Internal properties
-            Assert.False (Application.IsInitialized);
+            Assert.False (Application.Initialized);
             Assert.Equal (Application.GetSupportedCultures (), Application.SupportedCultures);
             Assert.Equal (Application.GetAvailableCulturesFromEmbeddedResources (), Application.SupportedCultures);
             Assert.False (Application._forceFakeConsole);
@@ -341,7 +341,7 @@ public class ApplicationTests
         CheckReset ();
 
         // Set the values that can be set
-        Application.IsInitialized = true;
+        Application.Initialized = true;
         Application._forceFakeConsole = true;
         Application.MainThreadId = 1;
 
@@ -524,7 +524,7 @@ public class ApplicationTests
     [AutoInitShutdown (verifyShutdown: true)]
     public void Internal_Properties_Correct ()
     {
-        Assert.True (Application.IsInitialized);
+        Assert.True (Application.Initialized);
         Assert.Null (Application.Top);
         RunState rs = Application.Begin (new ());
         Assert.Equal (Application.Top, rs.Toplevel);
diff --git a/UnitTests/Application/KeyboardTests.cs b/UnitTests/Application/KeyboardTests.cs
index ba472d3ab..9673e7b60 100644
--- a/UnitTests/Application/KeyboardTests.cs
+++ b/UnitTests/Application/KeyboardTests.cs
@@ -725,7 +725,7 @@ public class KeyboardTests
             iteration++;
             Assert.True (iteration < 2, "Too many iterations, something is wrong.");
 
-            if (Application.IsInitialized)
+            if (Application.Initialized)
             {
                 _output.WriteLine ("  Pressing QuitKey");
                 Application.RaiseKeyDownEvent (Application.QuitKey);
diff --git a/UnitTests/TestHelpers.cs b/UnitTests/TestHelpers.cs
index c27ab3da9..b3bfc0153 100644
--- a/UnitTests/TestHelpers.cs
+++ b/UnitTests/TestHelpers.cs
@@ -42,7 +42,7 @@ public class AutoInitShutdownAttribute : BeforeAfterTestAttribute
     ///     <see cref="ConsoleDriver"/> == <see cref="FakeDriver"/> and <paramref name="autoInit"/> is true.
     /// </param>
     /// <param name="configLocation">Determines what config file locations <see cref="ConfigurationManager"/> will load from.</param>
-    /// <param name="verifyShutdown">If true and <see cref="Application.IsInitialized"/> is true, the test will fail.</param>
+    /// <param name="verifyShutdown">If true and <see cref="Application.Initialized"/> is true, the test will fail.</param>
     public AutoInitShutdownAttribute (
         bool autoInit = true,
         Type consoleDriverType = null,
diff --git a/UnitTests/UICatalog/ScenarioTests.cs b/UnitTests/UICatalog/ScenarioTests.cs
index b87985b8f..fbd33effa 100644
--- a/UnitTests/UICatalog/ScenarioTests.cs
+++ b/UnitTests/UICatalog/ScenarioTests.cs
@@ -128,7 +128,7 @@ public class ScenarioTests : TestsAllViews
         void OnApplicationOnIteration (object s, IterationEventArgs a)
         {
             iterationCount++;
-            if (Application.IsInitialized)
+            if (Application.Initialized)
             {
                 // Press QuitKey 
                 _output.WriteLine ($"Attempting to quit with {Application.QuitKey}");