Merge branch 'master' into fixes/1169-toggle-dropdown-open

src/Avalonia.Controls/Control.cs

@@ -656,7 +656,6 @@ namespace Avalonia.Controls
         /// <param name="e">The event args.</param>
         protected virtual void OnAttachedToLogicalTree(LogicalTreeAttachmentEventArgs e)
         {
-            AttachedToLogicalTree?.Invoke(this, e);
         }
 
         /// <summary>
@@ -665,7 +664,6 @@ namespace Avalonia.Controls
         /// <param name="e">The event args.</param>
         protected virtual void OnDetachedFromLogicalTree(LogicalTreeAttachmentEventArgs e)
         {
-            DetachedFromLogicalTree?.Invoke(this, e);
         }
 
         /// <inheritdoc/>
@@ -842,6 +840,7 @@ namespace Avalonia.Controls
                 InitializeStylesIfNeeded(true);
 
                 OnAttachedToLogicalTree(e);
+                AttachedToLogicalTree?.Invoke(this, e);
             }
 
             foreach (var child in LogicalChildren.OfType<Control>())
@@ -862,6 +861,7 @@ namespace Avalonia.Controls
                 _isAttachedToLogicalTree = false;
                 _styleDetach.OnNext(this);
                 OnDetachedFromLogicalTree(e);
+                DetachedFromLogicalTree?.Invoke(this, e);
 
                 foreach (var child in LogicalChildren.OfType<Control>())
                 {

src/Avalonia.Input/MouseDevice.cs

@@ -20,6 +20,8 @@ namespace Avalonia.Input
         private int _clickCount;
         private Rect _lastClickRect;
         private uint _lastClickTime;
+        private IInputElement _captured;
+        private IDisposable _capturedSubscription;
        
         /// <summary>
         /// Gets the control that is currently capturing by the mouse, if any.
@@ -31,8 +33,23 @@ namespace Avalonia.Input
         /// </remarks>
         public IInputElement Captured
         {
-            get;
+            get => _captured;
-            protected set;
+            protected set
+            {
+                _capturedSubscription?.Dispose();
+                _capturedSubscription = null;
+
+                if (value != null)
+                {
+                    _capturedSubscription = Observable.FromEventPattern<VisualTreeAttachmentEventArgs>(
+                        x => value.DetachedFromVisualTree += x,
+                        x => value.DetachedFromVisualTree -= x)
+                        .Take(1)
+                        .Subscribe(_ => Captured = null);
+                }
+
+                _captured = value;
+            }
         }
         
         /// <summary>
@@ -55,6 +72,7 @@ namespace Avalonia.Input
         /// </remarks>
         public virtual void Capture(IInputElement control)
         {
+            // TODO: Check visibility and enabled state before setting capture.
             Captured = control;
         }
 

src/Avalonia.Visuals/Rendering/SceneGraph/Scene.cs

@@ -173,7 +173,7 @@ namespace Avalonia.Rendering.SceneGraph
                         }
                     }
 
-                    if (node.HitTest(p))
+                    if (node.HitTest(p) && node.Visual.IsAttachedToVisualTree)
                     {
                         yield return node.Visual;
                     }

src/Avalonia.Visuals/Visual.cs

@@ -329,6 +329,7 @@ namespace Avalonia
             }
 
             OnAttachedToVisualTree(e);
+            AttachedToVisualTree?.Invoke(this, e);
             InvalidateVisual();
 
             if (VisualChildren != null)
@@ -357,6 +358,7 @@ namespace Avalonia
             }
 
             OnDetachedFromVisualTree(e);
+            DetachedFromVisualTree?.Invoke(this, e);
             e.Root?.Renderer?.AddDirty(this);
 
             if (VisualChildren != null)
@@ -374,7 +376,6 @@ namespace Avalonia
         /// <param name="e">The event args.</param>
         protected virtual void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
         {
-            AttachedToVisualTree?.Invoke(this, e);
         }
 
         /// <summary>
@@ -383,7 +384,6 @@ namespace Avalonia
         /// <param name="e">The event args.</param>
         protected virtual void OnDetachedFromVisualTree(VisualTreeAttachmentEventArgs e)
         {
-            DetachedFromVisualTree?.Invoke(this, e);
         }
 
         /// <summary>

tests/Avalonia.Input.UnitTests/MouseDeviceTests.cs

@@ -1,6 +1,5 @@
 using Avalonia.Controls;
 using Avalonia.Input.Raw;
-using Avalonia.Layout;
 using Avalonia.Rendering;
 using Avalonia.UnitTests;
 using Avalonia.VisualTree;
@@ -12,6 +11,24 @@ namespace Avalonia.Input.UnitTests
 {
     public class MouseDeviceTests
     {
+        [Fact]
+        public void Capture_Is_Cleared_When_Control_Removed()
+        {
+            Canvas control;
+            var root = new TestRoot
+            {
+                Child = control = new Canvas(),
+            };
+            var target = new MouseDevice();
+
+            target.Capture(control);
+            Assert.Same(control, target.Captured);
+
+            root.Child = null;
+
+            Assert.Null(target.Captured);
+        }
+
         [Fact]
         public void MouseMove_Should_Update_PointerOver()
         {