chore: make previous changes adjustable in FeatureConfiguration

src/SamplesApp/SamplesApp.Shared/App.xaml.cs

@@ -546,6 +546,7 @@ static void ConfigureFeatureFlags()
 #if HAS_UNO
 			Uno.UI.FeatureConfiguration.TextBox.UseOverlayOnSkia = false;
 			Uno.UI.FeatureConfiguration.ToolTip.UseToolTips = true;
+			Uno.UI.FeatureConfiguration.DependencyProperty.ValidatePropertyOwnerOnReadWrite = true;
 
 			Uno.UI.FeatureConfiguration.Font.DefaultTextFontFamily = "ms-appx:///Uno.Fonts.OpenSans/Fonts/OpenSans.ttf";
 #endif

src/Uno.UI.RuntimeTests/MUX/Helpers/EventTester.cs

@@ -15,6 +15,7 @@
 using Microsoft.UI.Xaml;
 using UIExecutor = MUXControlsTestApp.Utilities.RunOnUIThread;
 using MUXControlsTestApp.Utilities;
+using Uno.UI;
 
 namespace Microsoft/* UWP don't rename */.UI.Xaml.Tests.Common
 {
@@ -153,7 +154,7 @@ public static EventTester<UIElement, TEventArgs> FromRoutedEvent(UIElement sende
 			return new RoutedEventTester<TEventArgs>(sender, eventName, action);
 		}
 
-		public TimeSpan DefaultTimeout = EventTesterConfig.Timeout;
+		public TimeSpan DefaultTimeout = FeatureConfiguration.DebugOptions.WaitIndefinitelyInEventTester ? TimeSpan.FromMilliseconds(-1) : EventTesterConfig.Timeout;
 
 		private TSender Sender
 		{

src/Uno.UI/FeatureConfiguration.cs

@@ -841,6 +841,29 @@ public static class DependencyProperty
 			/// of having an undefined behavior and/or race conditions.
 			/// </summary>
 			public static bool DisableThreadingCheck { get; set; }
+
+			/// <summary>
+			/// Enables checks that make sure that <see cref="DependencyObjectStore.GetValue" /> and
+			/// <see cref="DependencyObjectStore.SetValue" /> are only called on the owner of the property being
+			/// set/got.
+			/// </summary>
+			public static bool ValidatePropertyOwnerOnReadWrite { get; set; } =
+#if DEBUG
+				true;
+#else
+				global::System.Diagnostics.Debugger.IsAttached;
+#endif
+		}
+
+		/// <summary>
+		/// This is for internal use to facilitate turning on/off certain logic that makes it easier/harder
+		/// to debug.
+		/// </summary>
+		internal static class DebugOptions
+		{
+			public static bool PreventKeyboardStateTrackerFromResettingOnWindowActivationChange { get; set; }
+
+			public static bool WaitIndefinitelyInEventTester { get; set; }
 		}
 	}
 }

src/Uno.UI/UI/Xaml/DependencyObjectStore.cs

@@ -790,24 +790,25 @@ private void WritePropertyEventTrace(int eventId, DependencyProperty property, D
 		[MethodImpl(MethodImplOptions.AggressiveInlining)]
 		private void ValidatePropertyOwner(DependencyProperty property)
 		{
-#if DEBUG
-			var isFrameworkElement = _originalObjectType.Is(typeof(FrameworkElement));
-			var isMixinFrameworkElement = _originalObjectRef.Target is IFrameworkElement && !isFrameworkElement;
+			if (FeatureConfiguration.DependencyProperty.ValidatePropertyOwnerOnReadWrite)
+			{
+				var isFrameworkElement = _originalObjectType.Is(typeof(FrameworkElement));
+				var isMixinFrameworkElement = _originalObjectRef.Target is IFrameworkElement && !isFrameworkElement;
 
-			if (
-				!_originalObjectType.Is(property.OwnerType)
-				&& !property.IsAttached
+				if (
+					!_originalObjectType.Is(property.OwnerType)
+					&& !property.IsAttached
 
-				// Don't fail validation for properties that are located on non-FrameworkElement types
-				// e.g. ScrollContentPresenter, for which using the Name property should not fail.
-				&& !isMixinFrameworkElement
-			)
-			{
-				throw new InvalidOperationException(
-					$"The Dependency Property [{property.Name}] is owned by [{property.OwnerType}] and cannot be used on [{_originalObjectType}]"
-				);
+					// Don't fail validation for properties that are located on non-FrameworkElement types
+					// e.g. ScrollContentPresenter, for which using the Name property should not fail.
+					&& !isMixinFrameworkElement
+				)
+				{
+					throw new InvalidOperationException(
+						$"The Dependency Property [{property.Name}] is owned by [{property.OwnerType}] and cannot be used on [{_originalObjectType}]"
+					);
+				}
 			}
-#endif
 		}
 
 		public long RegisterPropertyChangedCallback(DependencyProperty property, DependencyPropertyChangedCallback callback)

src/Uno.UI/UI/Xaml/Window/Implementations/BaseWindowImplementation.cs

@@ -270,7 +270,10 @@ private void OnActivationStateChanged(CoreWindowActivationState state)
 		CoreWindow?.OnActivated(coreWindowActivatedEventArgs);
 		Activated?.Invoke(Window, activatedEventArgs);
 		SystemThemeHelper.RefreshSystemTheme();
-		KeyboardStateTracker.Reset();
+		if (!FeatureConfiguration.DebugOptions.PreventKeyboardStateTrackerFromResettingOnWindowActivationChange)
+		{
+			KeyboardStateTracker.Reset();
+		}
 	}
 
 	public bool Close()

src/Uno.UWP/Buffers/DefaultArrayPoolBucket.cs

@@ -44,7 +44,7 @@ internal Bucket(int bufferLength, int numberOfBuffers, int poolId)
 #if DEBUG // thread tracking adds non-trivial overheads to Enter/Exit
 					true
 #else
-					false
+					global::System.Diagnostics.Debugger.IsAttached
 #endif
 					);
 				_buffers = new T[numberOfBuffers][];