diff --git a/UnitTests/FileServices/FileDialogTests.cs b/UnitTests/FileServices/FileDialogTests.cs
index 1395543ee..ec72a7add 100644
--- a/UnitTests/FileServices/FileDialogTests.cs
+++ b/UnitTests/FileServices/FileDialogTests.cs
@@ -622,6 +622,11 @@ public class FileDialogTests (ITestOutputHelper output)
 
     private FileDialog GetWindowsDialog ()
     {
+        // Override CM
+        Window.DefaultBorderStyle = LineStyle.Single;
+        Dialog.DefaultButtonAlignment = Alignment.Center;
+        Dialog.DefaultBorderStyle = LineStyle.Single;
+
         // Arrange
         var fileSystem = new MockFileSystem (new Dictionary<string, MockFileData> (), @"c:\");
         fileSystem.MockTime (() => new (2010, 01, 01, 11, 12, 43));
diff --git a/UnitTests/Views/MenuBarTests.cs b/UnitTests/Views/MenuBarTests.cs
index f7804dd42..330f8bacf 100644
--- a/UnitTests/Views/MenuBarTests.cs
+++ b/UnitTests/Views/MenuBarTests.cs
@@ -362,6 +362,11 @@ public class MenuBarTests (ITestOutputHelper output)
     [AutoInitShutdown]
     public void Draw_A_Menu_Over_A_Dialog ()
     {
+        // Override CM
+        Window.DefaultBorderStyle = LineStyle.Single;
+        Dialog.DefaultButtonAlignment = Alignment.Center;
+        Dialog.DefaultBorderStyle = LineStyle.Single;
+
         Toplevel top = new ();
         var win = new Window ();
         top.Add (win);
@@ -590,6 +595,11 @@ public class MenuBarTests (ITestOutputHelper output)
     [AutoInitShutdown]
     public void Draw_A_Menu_Over_A_Top_Dialog ()
     {
+        // Override CM
+        Window.DefaultBorderStyle = LineStyle.Single;
+        Dialog.DefaultButtonAlignment = Alignment.Center;
+        Dialog.DefaultBorderStyle = LineStyle.Single;
+
         ((FakeDriver)Application.Driver).SetBufferSize (40, 15);
 
         Assert.Equal (new (0, 0, 40, 15), Application.Driver.Clip);