refactor: Cleanup hit test coercion

src/Uno.UI.Runtime.Skia.Wpf/Input/WpfCorePointerInputSource.cs

@@ -141,7 +141,7 @@ private void HostOnMouseEvent(InputEventArgs args, TypedEventHandler<object, Poi
 
 			// Is the pointer inside an element in the flyout layer? if so, raise in managed
 			var xamlRoot = WpfManager.XamlRootMap.GetRootForHost((IWpfXamlRootHost)_host!);
-			var managedHitTestResult = Microsoft.UI.Xaml.Media.VisualTreeHelper.SearchDownForTopMostElementAt(eventArgs.CurrentPoint.Position, xamlRoot!.VisualTree.PopupRoot!, Microsoft.UI.Xaml.Media.VisualTreeHelper.DefaultGetTestability, null);
+			var managedHitTestResult = Microsoft.UI.Xaml.Media.VisualTreeHelper.SearchDownForTopMostElementAt(eventArgs.CurrentPoint.Position, xamlRoot!.VisualTree.PopupRoot!, isForDrop: false, isStale: null, forceCollapsed: null);
 			if (managedHitTestResult.element is { })
 			{
 				@event?.Invoke(this, eventArgs);

src/Uno.UI.RuntimeTests/Tests/Windows_UI_Xaml/Given_UIElement.wasm.cs

@@ -49,20 +49,6 @@ public void When_HTMLElement_ExternalElement_Override()
 			Assert.AreEqual("p", SUT.HtmlTag);
 		}
 
-		[TestMethod]
-		[RunsOnUIThread]
-		public async Task When_HTMLElement_ExternalElement_Override_Then_IsHitTestable()
-		{
-			var SUT = new MyCustomComponent();
-
-			TestServices.WindowHelper.WindowContent = SUT;
-			await TestServices.WindowHelper.WaitForIdle();
-			await TestServices.WindowHelper.WaitFor(() => SUT.IsLoaded);
-			await TestServices.WindowHelper.WaitForIdle();
-
-			Assert.AreEqual(HitTestability.Visible, SUT.HitTestVisibility);
-		}
-
 		[TestMethod]
 		[RunsOnUIThread]
 		public void When_HTMLElement_ExternalElement_Override_Twice()

src/Uno.UI.RuntimeTests/Tests/Windows_UI_Xaml_Media/Given_VisualTreeHelper.cs

@@ -80,12 +80,9 @@ public async Task When_Nested_In_Native_View()
 			var expected = new Rect(25, 205, 80, 40);
 			RectAssert.AreEqual(expected, bounds);
 
-			GetHitTestability getHitTestability = null;
-			getHitTestability = element => (element as FrameworkElement)?.Background != null ? (element.GetHitTestVisibility(), getHitTestability) : (HitTestability.Invisible, getHitTestability);
-
 			foreach (var point in GetPointsInside(bounds, perimeterOffset: 5))
 			{
-				var hitTest = VisualTreeHelper.HitTest(point, WindowHelper.WindowContent.XamlRoot, getHitTestability);
+				var hitTest = VisualTreeHelper.HitTest(point, WindowHelper.WindowContent.XamlRoot);
 				Assert.AreEqual(sut, hitTest.element);
 			}
 

src/Uno.UI/UI/Xaml/Controls/Border/Border.cs

@@ -307,6 +307,10 @@ protected override void OnBackgroundChanged(DependencyPropertyChangedEventArgs e
 		UpdateBorder();
 #endif
 		OnBackgroundChangedPartial();
+
+#if __WASM__
+		RefreshPointerEvents();
+#endif
 	}
 
 	partial void OnBackgroundChangedPartial();

src/Uno.UI/UI/Xaml/Controls/ContentPresenter/ContentPresenter.skia.cs

@@ -42,8 +42,6 @@ partial void InitializePlatform()
 		});
 	}
 
-	private IDisposable _nativeElementDisposable;
-
 	partial void TryRegisterNativeElement(object oldValue, object newValue)
 	{
 		if (IsNativeHost && IsInLiveTree)
@@ -130,11 +128,6 @@ partial void AttachNativeElement()
 		_nativeHosts.Add(this);
 		EffectiveViewportChanged += OnEffectiveViewportChanged;
 		LayoutUpdated += OnLayoutUpdated;
-		var visiblityToken = RegisterPropertyChangedCallback(HitTestVisibilityProperty, OnHitTestVisiblityChanged);
-		_nativeElementDisposable = Disposable.Create(() =>
-		{
-			UnregisterPropertyChangedCallback(HitTestVisibilityProperty, visiblityToken);
-		});
 	}
 
 	partial void DetachNativeElement(object content)
@@ -147,7 +140,6 @@ partial void DetachNativeElement(object content)
 		EffectiveViewportChanged -= OnEffectiveViewportChanged;
 		LayoutUpdated -= OnLayoutUpdated;
 		_nativeElementHostingExtension.Value!.DetachNativeElement(content);
-		_nativeElementDisposable?.Dispose();
 	}
 
 	private Size MeasureNativeElement(Size childMeasuredSize, Size availableSize)
@@ -156,11 +148,6 @@ private Size MeasureNativeElement(Size childMeasuredSize, Size availableSize)
 		return _nativeElementHostingExtension.Value!.MeasureNativeElement(Content, childMeasuredSize, availableSize);
 	}
 
-	private void OnHitTestVisiblityChanged(DependencyObject sender, DependencyProperty dp)
-	{
-		_nativeElementHostingExtension.Value!.ChangeNativeElementVisibility(Content, HitTestVisibility != HitTestability.Collapsed);
-	}
-
 	internal static void UpdateNativeHostContentPresentersOpacities()
 	{
 		foreach (var contentPresenter in _nativeHosts)
@@ -179,6 +166,8 @@ internal static void UpdateNativeHostContentPresentersOpacities()
 
 	private void OnLayoutUpdated(object sender, object e)
 	{
+		_nativeElementHostingExtension.Value!.ChangeNativeElementVisibility(Content, this.GetHitTestVisibility() != HitTestability.Collapsed);
+
 		// Not quite sure why we need to queue the arrange call, but the native element either explodes or doesn't
 		// respect alignments correctly otherwise. This is particularly relevant for the initial load.
 		DispatcherQueue.TryEnqueue(ArrangeNativeElement);

src/Uno.UI/UI/Xaml/Controls/Control/Control.cs

@@ -116,10 +116,6 @@ public bool IsEnabled
 
 		private void OnIsEnabledChanged(DependencyPropertyChangedEventArgs args)
 		{
-#if UNO_HAS_MANAGED_POINTERS || __WASM__
-			UpdateHitTest();
-#endif
-
 			_isEnabledChangedEventArgs ??= new IsEnabledChangedEventArgs();
 			_isEnabledChangedEventArgs.SourceEvent = args;
 
@@ -143,7 +139,11 @@ private void OnIsEnabledChanged(DependencyPropertyChangedEventArgs args)
 			{
 				UpdateDOMProperties();
 			}
+
+			RefreshPointerEvents();
 #endif
+
+			ClearPointersStateIfNeeded();
 		}
 		#endregion
 

src/Uno.UI/UI/Xaml/Controls/Flyout/FlyoutPopupPanel.cs

@@ -58,8 +58,7 @@ private protected override void OnPointerPressedDismissed(PointerRoutedEventArgs
 		}
 
 		var point = args.GetCurrentPoint(null);
-		var hitTestIgnoringThis = VisualTreeHelper.DefaultGetTestability.Except(XamlRoot?.VisualTree.PopupRoot as UIElement ?? this);
-		var (elementHitUnderOverlay, _) = VisualTreeHelper.HitTest(point.Position, passThroughElement.XamlRoot, hitTestIgnoringThis);
+		var (elementHitUnderOverlay, _) = VisualTreeHelper.HitTest(point.Position, passThroughElement.XamlRoot, forceCollapsed: XamlRoot?.VisualTree.PopupRoot as UIElement ?? this);
 
 		if (elementHitUnderOverlay is null)
 		{

src/Uno.UI/UI/Xaml/Controls/Image/Image.wasm.cs

@@ -90,7 +90,7 @@ private ExceptionRoutedEventArgs ImageFailedConverter(object sender, string e)
 
 		partial void OnSourceChanged(ImageSource newValue, bool forceReload)
 		{
-			UpdateHitTest();
+			RefreshPointerEvents();
 
 			_lastMeasuredSize = _zeroSize;
 			// Hide the old image until the new image is loaded. This is the behaviour on WinUI.

src/Uno.UI/UI/Xaml/Controls/Panel/Panel.cs

@@ -238,6 +238,10 @@ protected override void OnBackgroundChanged(DependencyPropertyChangedEventArgs e
 		UpdateBorder();
 #endif
 		OnBackgroundChangedPartial();
+
+#if __WASM__
+		RefreshPointerEvents();
+#endif
 	}
 
 	partial void OnBackgroundChangedPartial();

src/Uno.UI/UI/Xaml/Controls/TextBlock/TextBlock.wasm.cs

@@ -192,8 +192,6 @@ partial void OnIsTextSelectionEnabledChangedPartial()
 		partial void OnTextChangedPartial()
 		{
 			_textChanged = true;
-
-			UpdateHitTest();
 		}
 
 		partial void ClearTextPartial() => SetHtmlContent("");

src/Uno.UI/UI/Xaml/Documents/Hyperlink.wasm.cs

@@ -67,11 +67,7 @@ private void UpdateNavigationProperties(Uri navigateUri, NavigationTarget target
 					("href", uri)
 				);
 			}
-			UpdateHitTest();
 		}
-
-		internal override bool IsViewHit()
-			=> NavigateUri != null || base.IsViewHit();
 	}
 
 	public enum NavigationTarget

src/Uno.UI/UI/Xaml/DragDrop/DropUITarget.cs

@@ -14,20 +14,6 @@ namespace Microsoft.UI.Xaml
 {
 	internal class DropUITarget(XamlRoot xamlRoot) : ICoreDropOperationTarget
 	{
-		private static GetHitTestability? _getDropHitTestability;
-		private static GetHitTestability GetDropHitTestability => _getDropHitTestability ??= (elt =>
-		{
-			var visiblity = elt.GetHitTestVisibility();
-			return visiblity switch
-			{
-				HitTestability.Collapsed => (HitTestability.Collapsed, _getDropHitTestability!),
-				// Once we reached an element that AllowDrop, we only validate the hit testability for its children
-				_ when elt.AllowDrop => (visiblity, VisualTreeHelper.DefaultGetTestability),
-				_ => (HitTestability.Invisible, _getDropHitTestability!)
-			};
-		});
-
-
 		// Note: As drag events are routed (so they may be received by multiple elements), we might not have an entry for each drop targets.
 		//		 We will instead have entry only for leaf (a.k.a. OriginalSource).
 		//		 This is valid as UWP does clear the UIOverride as soon as a DragLeave is raised, no matter the number of drop target under pointer.
@@ -116,7 +102,7 @@ public IAsyncOperation<DataPackageOperation> DropAsync(CoreDragInfo dragInfo)
 			var target = VisualTreeHelper.HitTest(
 				dragInfo.Position,
 				xamlRoot,
-				getTestability: GetDropHitTestability,
+				isForDrop: true,
 				isStale: new StalePredicate(elt => elt.IsDragOver(dragInfo.SourceId), "IsDragOver"));
 
 			// First raise the drag leave event on stale branch if any.

src/Uno.UI/UI/Xaml/FrameworkElement.unittests.cs

@@ -18,8 +18,6 @@ public partial class FrameworkElement : IEnumerable
 
 		internal bool ShouldInterceptInvalidate { get; set; }
 
-		internal void UpdateHitTest() { }
-
 		private protected virtual void OnPostLoading() { }
 
 		partial void OnLoadingPartial();

src/Uno.UI/UI/Xaml/Media/VisualTreeHelper.cs

@@ -422,13 +422,12 @@ internal static IReadOnlyList<_View> ClearChildren(UIElement view)
 #endif
 		}
 
-		internal static readonly GetHitTestability DefaultGetTestability = elt => (elt.GetHitTestVisibility(), DefaultGetTestability!);
-
 		internal static (UIElement? element, Branch? stale) HitTest(
 			Point position,
 			XamlRoot? xamlRoot,
-			GetHitTestability? getTestability = null,
-			StalePredicate? isStale = null
+			bool isForDrop = false,
+			StalePredicate? isStale = null,
+			UIElement? forceCollapsed = null
 #if TRACE_HIT_TESTING
 			, [CallerMemberName] string caller = "")
 		{
@@ -440,7 +439,7 @@ internal static (UIElement? element, Branch? stale) HitTest(
 #endif
 			if (xamlRoot?.VisualTree.RootElement is UIElement root)
 			{
-				return SearchDownForTopMostElementAt(position, root, getTestability ?? DefaultGetTestability, isStale);
+				return SearchDownForTopMostElementAt(position, root, isForDrop, isStale, forceCollapsed);
 			}
 
 			return default;
@@ -453,20 +452,22 @@ internal static (UIElement? element, Branch? stale) HitTest(
 		internal static (UIElement? element, Branch? stale) SearchDownForTopMostElementAt(
 			Point position,
 			UIElement element,
-			GetHitTestability getVisibility,
-			StalePredicate? isStale)
+			bool isForDrop,
+			StalePredicate? isStale,
+			UIElement? forceCollapsed)
 		{
 			var stale = default(Branch?);
-			HitTestability elementHitTestVisibility;
-			(elementHitTestVisibility, getVisibility) = getVisibility(element);
 
 #if TRACE_HIT_TESTING
 			using var _ = SET_TRACE_SUBJECT(element);
-			TRACE($"- hit test visibility: {elementHitTestVisibility}");
 #endif
+			if (isForDrop && element.AllowDrop)
+			{
+				isForDrop = false;
+			}
 
 			// If the element is not hit testable, do not even try to validate it nor its children.
-			if (elementHitTestVisibility == HitTestability.Collapsed)
+			if (element.Visibility == Visibility.Collapsed || !element.IsEnabledOverride() || !element.IsHitTestVisible || element == forceCollapsed)
 			{
 				// Even if collapsed, if the element is stale, we search down for the real stale leaf
 				if (isStale?.Method.Invoke(element) ?? false)
@@ -592,7 +593,7 @@ internal static (UIElement? element, Branch? stale) SearchDownForTopMostElementA
 
 			while (child.MoveNext())
 			{
-				var childResult = SearchDownForTopMostElementAt(testPosition, child.Current!, getVisibility, isChildStale);
+				var childResult = SearchDownForTopMostElementAt(testPosition, child.Current!, isForDrop, isChildStale, forceCollapsed);
 
 				// If we found a stale element in child sub-tree, keep it and stop looking for stale elements
 				if (childResult.stale is not null)
@@ -662,7 +663,7 @@ internal static (UIElement? element, Branch? stale) SearchDownForTopMostElementA
 
 			// We didn't find any child at the given position, validate that element can be touched (i.e. not HitTestability.Invisible),
 			// and the position is in actual bounds (which might be different than the clipping bounds)
-			if (elementHitTestVisibility == HitTestability.Visible && renderingBounds.Contains(testPosition))
+			if (!isForDrop && element.IsViewHitOrTagExternallyDefined() && renderingBounds.Contains(testPosition))
 			{
 				TRACE($"> LEAF! ({element.GetDebugName()} is the OriginalSource) | stale branch: {stale?.ToString() ?? "-- none --"}");
 				return (element, stale);

src/Uno.UI/UI/Xaml/Shapes/Shape.cs

@@ -155,7 +155,13 @@ public DoubleCollection StrokeDashArray
 		#endregion
 
 		internal override bool IsViewHit()
+#if __WASM__
+			// We stay at the default "pointer-events: none" defined in Uno.UI.css in class svg.uno-uielement.
+			// This is required to avoid this SVG element (which is actually only a collection) to stoll pointer events.
+			=> false;
+#else
 			=> Fill != null; // Do not invoke base.IsViewHit(): We don't have to have de FrameworkElement.Background to be hit testable!
+#endif
 
 		protected override void OnBackgroundChanged(DependencyPropertyChangedEventArgs e)
 		{

src/Uno.UI/UI/Xaml/Shapes/Shape.wasm.cs

@@ -42,13 +42,6 @@ private protected void UpdateRender()
 			UpdateStrokeDashArray();
 		}
 
-
-		private protected override void OnHitTestVisibilityChanged(HitTestability oldValue, HitTestability newValue)
-		{
-			// We don't invoke the base, so we stay at the default "pointer-events: none" defined in Uno.UI.css in class svg.uno-uielement.
-			// This is required to avoid this SVG element (which is actually only a collection) to stoll pointer events.
-		}
-
 		private void OnFillBrushChanged()
 		{
 			// We don't request an update of the HitTest (UpdateHitTest()) since this element is never expected to be hit testable.