Merge branch 'fixes/TextWrapAndTrim' of https://github.com/Gillibald/Avalonia into fixes/TextWrapAndTrim

samples/ControlCatalog/App.xaml.cs

@@ -29,11 +29,19 @@ namespace ControlCatalog
         {
             new StyleInclude(new Uri("resm:Styles?assembly=ControlCatalog"))
             {
-                Source = new Uri("resm:Avalonia.Themes.Default.Accents.BaseLight.xaml?assembly=Avalonia.Themes.Default")
+                Source = new Uri("avares://Avalonia.Themes.Fluent/Accents/Base.xaml")
             },
             new StyleInclude(new Uri("resm:Styles?assembly=ControlCatalog"))
             {
-                Source = new Uri("resm:Avalonia.Themes.Default.DefaultTheme.xaml?assembly=Avalonia.Themes.Default")
+                Source = new Uri("avares://Avalonia.Themes.Fluent/Accents/BaseLight.xaml")
+            },
+            new StyleInclude(new Uri("resm:Styles?assembly=ControlCatalog"))
+            {
+                Source = new Uri("avares://Avalonia.Themes.Default/Accents/BaseLight.xaml")
+            },
+            new StyleInclude(new Uri("resm:Styles?assembly=ControlCatalog"))
+            {
+                Source = new Uri("avares://Avalonia.Themes.Default/DefaultTheme.xaml")
             },
         };
 
@@ -41,11 +49,19 @@ namespace ControlCatalog
         {
             new StyleInclude(new Uri("resm:Styles?assembly=ControlCatalog"))
             {
-                Source = new Uri("resm:Avalonia.Themes.Default.Accents.BaseDark.xaml?assembly=Avalonia.Themes.Default")
+                Source = new Uri("avares://Avalonia.Themes.Fluent/Accents/Base.xaml")
+            },
+            new StyleInclude(new Uri("resm:Styles?assembly=ControlCatalog"))
+            {
+                Source = new Uri("avares://Avalonia.Themes.Fluent/Accents/BaseDark.xaml")
+            },
+            new StyleInclude(new Uri("resm:Styles?assembly=ControlCatalog"))
+            {
+                Source = new Uri("avares://Avalonia.Themes.Default/Accents/BaseDark.xaml")
             },
             new StyleInclude(new Uri("resm:Styles?assembly=ControlCatalog"))
             {
-                Source = new Uri("resm:Avalonia.Themes.Default.DefaultTheme.xaml?assembly=Avalonia.Themes.Default")
+                Source = new Uri("avares://Avalonia.Themes.Default/DefaultTheme.xaml")
             },
         };
 

samples/ControlCatalog/MainView.xaml

@@ -2,7 +2,6 @@
         xmlns:pages="clr-namespace:ControlCatalog.Pages"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         x:Class="ControlCatalog.MainView"
-        Background="Black"
         Foreground="{DynamicResource ThemeForegroundBrush}"
         FontSize="{DynamicResource FontSizeNormal}">
   <Grid>

samples/RenderDemo/App.xaml

@@ -3,8 +3,7 @@
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
     x:Class="RenderDemo.App">
     <Application.Styles>
-        <StyleInclude Source="avares://Avalonia.Themes.Default/DefaultTheme.xaml"/>
-        <StyleInclude Source="avares://Avalonia.Themes.Default/Accents/BaseLight.xaml"/>
+        <StyleInclude Source="avares://Avalonia.Themes.Fluent/Accents/FluentLight.xaml"/>
         <StyleInclude Source="avares://RenderDemo/SideBar.xaml"/>
     </Application.Styles>
-</Application>
+</Application>

samples/RenderDemo/SideBar.xaml

@@ -1,65 +1,68 @@
 <Styles xmlns="https://github.com/avaloniaui"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
-    <Style Selector="TabControl.sidebar">
-        <Setter Property="TabStripPlacement" Value="Left"/>
-        <Setter Property="Padding" Value="8 0 0 0"/>
-        <Setter Property="Background" Value="{DynamicResource SystemAccentColor}"/>
-        <Setter Property="Template">
-            <ControlTemplate>
-                <Border 
-                    Margin="{TemplateBinding Margin}"
-                    BorderBrush="{TemplateBinding BorderBrush}"
-                    BorderThickness="{TemplateBinding BorderThickness}">
-                    <DockPanel>
-                        <ScrollViewer
-                            Name="PART_ScrollViewer"
-                            HorizontalScrollBarVisibility="{TemplateBinding (ScrollViewer.HorizontalScrollBarVisibility)}"
-                            VerticalScrollBarVisibility="{TemplateBinding (ScrollViewer.VerticalScrollBarVisibility)}"
-                            Background="{TemplateBinding Background}">
-                            <ItemsPresenter
-                                Name="PART_ItemsPresenter"                          
-                                Items="{TemplateBinding Items}"
-                                ItemsPanel="{TemplateBinding ItemsPanel}"
-                                ItemTemplate="{TemplateBinding ItemTemplate}">
-                            </ItemsPresenter>
-                        </ScrollViewer>
-                        <ContentPresenter
-                            Name="PART_SelectedContentHost"
-                            Margin="{TemplateBinding Padding}"                           
-                            HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
-                            VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
-                            Content="{TemplateBinding SelectedContent}"
-                            ContentTemplate="{TemplateBinding SelectedContentTemplate}">
-                        </ContentPresenter>
-                    </DockPanel>
-                </Border>
-            </ControlTemplate>
-        </Setter>
-    </Style>
+  <Style Selector="TabControl.sidebar">
+    <Setter Property="TabStripPlacement" Value="Left"/>
+    <Setter Property="Padding" Value="8 0 0 0"/>
+    <Setter Property="Background" Value="{DynamicResource SystemAccentColor}"/>
+    <Setter Property="Template">
+      <ControlTemplate>
+        <Border
+            Margin="{TemplateBinding Margin}"
+            BorderBrush="{TemplateBinding BorderBrush}"
+            BorderThickness="{TemplateBinding BorderThickness}">
+          <DockPanel>
+            <ScrollViewer
+                Name="PART_ScrollViewer"
+                HorizontalScrollBarVisibility="{TemplateBinding (ScrollViewer.HorizontalScrollBarVisibility)}"
+                VerticalScrollBarVisibility="{TemplateBinding (ScrollViewer.VerticalScrollBarVisibility)}"
+                Background="{TemplateBinding Background}">
+              <ItemsPresenter
+                  Name="PART_ItemsPresenter"
+                  Items="{TemplateBinding Items}"
+                  ItemsPanel="{TemplateBinding ItemsPanel}"
+                  ItemTemplate="{TemplateBinding ItemTemplate}">
+              </ItemsPresenter>
+            </ScrollViewer>
+            <ContentPresenter
+                Name="PART_SelectedContentHost"
+                Margin="{TemplateBinding Padding}"
+                HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
+                VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
+                Content="{TemplateBinding SelectedContent}"
+                ContentTemplate="{TemplateBinding SelectedContentTemplate}">
+            </ContentPresenter>
+          </DockPanel>
+        </Border>
+      </ControlTemplate>
+    </Setter>
+  </Style>
 
-    <Style Selector="TabControl.sidebar > TabItem">       
-        <Setter Property="BorderThickness" Value="0"/>
-        <Setter Property="Foreground" Value="White"/>
-        <Setter Property="FontSize" Value="14"/>
-        <Setter Property="Margin" Value="0"/>
-        <Setter Property="Padding" Value="16"/>
-        <Setter Property="Opacity" Value="0.5"/>
-        <Setter Property="Transitions">
-            <Transitions>
-                <DoubleTransition Property="Opacity" Duration="0:0:0.150"/>
-            </Transitions>
-        </Setter>
-    </Style>
-    <Style Selector="TabControl.sidebar > TabItem:pointerover">
-        <Setter Property="Opacity" Value="1"/>
-    </Style>
-    <Style Selector="TabControl.sidebar > TabItem:pointerover /template/ ContentPresenter#PART_ContentPresenter">
-        <Setter Property="Background" Value="Transparent"/>
-    </Style>
-    <Style Selector="TabControl.sidebar > TabItem:selected">
-        <Setter Property="Opacity" Value="1"/>
-    </Style>
-    <Style Selector="TabControl.sidebar > TabItem:selected /template/ ContentPresenter#PART_ContentPresenter">
-        <Setter Property="Background" Value="{DynamicResource SystemAccentColorLight1}"/>
-    </Style>
+  <Style Selector="TabControl.sidebar > TabItem">
+    <Setter Property="BorderThickness" Value="0"/>
+    <Setter Property="Foreground" Value="White"/>
+    <Setter Property="FontSize" Value="14"/>
+    <Setter Property="Margin" Value="0"/>
+    <Setter Property="Padding" Value="16"/>
+    <Setter Property="Opacity" Value="0.5"/>
+    <Setter Property="Transitions">
+      <Transitions>
+        <DoubleTransition Property="Opacity" Duration="0:0:0.150"/>
+      </Transitions>
+    </Setter>
+  </Style>
+  <Style Selector="TabControl.sidebar > TabItem:selected /template/ Border#PART_SelectedPipe">
+    <Setter Property="IsVisible" Value="False" />
+  </Style>
+  <Style Selector="TabControl.sidebar > TabItem:pointerover">
+    <Setter Property="Opacity" Value="1"/>
+  </Style>
+  <Style Selector="TabControl.sidebar > TabItem:pointerover /template/ Border#PART_LayoutRoot">
+    <Setter Property="Background" Value="{DynamicResource SystemAccentColorLight2}"/>
+  </Style>
+  <Style Selector="TabControl.sidebar > TabItem:selected">
+    <Setter Property="Opacity" Value="1"/>
+  </Style>
+  <Style Selector="TabControl.sidebar > TabItem:selected /template/ Border#PART_LayoutRoot">
+    <Setter Property="Background" Value="{DynamicResource SystemAccentColorLight1}"/>
+  </Style>
 </Styles>

src/Avalonia.Base/Threading/AvaloniaSynchronizationContext.cs

@@ -1,3 +1,5 @@
+using System;
+using System.Runtime.ConstrainedExecution;
 using System.Threading;
 
 namespace Avalonia.Threading
@@ -7,6 +9,20 @@ namespace Avalonia.Threading
     /// </summary>
     public class AvaloniaSynchronizationContext : SynchronizationContext
     {
+        public interface INonPumpingPlatformWaitProvider
+        {
+            int Wait(IntPtr[] waitHandles, bool waitAll, int millisecondsTimeout);
+        }
+
+        private readonly INonPumpingPlatformWaitProvider _waitProvider;
+
+        public AvaloniaSynchronizationContext(INonPumpingPlatformWaitProvider waitProvider)
+        {
+            _waitProvider = waitProvider;
+            if (_waitProvider != null)
+                SetWaitNotificationRequired();
+        }
+
         /// <summary>
         /// Controls if SynchronizationContext should be installed in InstallIfNeeded. Used by Designer.
         /// </summary>
@@ -22,7 +38,8 @@ namespace Avalonia.Threading
                 return;
             }
 
-            SetSynchronizationContext(new AvaloniaSynchronizationContext());
+            SetSynchronizationContext(new AvaloniaSynchronizationContext(AvaloniaLocator.Current
+                .GetService<INonPumpingPlatformWaitProvider>()));
         }
 
         /// <inheritdoc/>
@@ -39,5 +56,13 @@ namespace Avalonia.Threading
             else
                 Dispatcher.UIThread.InvokeAsync(() => d(state), DispatcherPriority.Send).Wait();
         }
+
+        [PrePrepareMethod]
+        public override int Wait(IntPtr[] waitHandles, bool waitAll, int millisecondsTimeout)
+        {
+            if (_waitProvider != null)
+                return _waitProvider.Wait(waitHandles, waitAll, millisecondsTimeout);
+            return base.Wait(waitHandles, waitAll, millisecondsTimeout);
+        }
     }
 }

src/Avalonia.Controls/RelativePanel.cs

@@ -54,7 +54,7 @@ namespace Avalonia.Controls
             }
             _childGraph.Measure(availableSize);
 
-            _childGraph.Reset();
+            _childGraph.Reset(false);
             var boundingSize = _childGraph.GetBoundingSize(Width.IsNaN(), Height.IsNaN());
             _childGraph.Reset();
             _childGraph.Measure(boundingSize);
@@ -119,17 +119,22 @@ namespace Avalonia.Controls
 
             public void Arrange(Size arrangeSize) => Element.Arrange(new Rect(Left, Top, Math.Max(arrangeSize.Width - Left - Right, 0), Math.Max(arrangeSize.Height - Top - Bottom, 0)));
 
-            public void Reset()
+            public void Reset(bool clearPos)
             {
-                Left = double.NaN;
-                Top = double.NaN;
-                Right = double.NaN;
-                Bottom = double.NaN;
+                if (clearPos)
+                {
+                    Left = double.NaN;
+                    Top = double.NaN;
+                    Right = double.NaN;
+                    Bottom = double.NaN;
+                }
+
                 Measured = false;
             }
 
             public Size GetBoundingSize()
             {
+                if (Left < 0 || Top < 0) return default;
                 if (Measured)
                     return BoundingSize;
 
@@ -209,7 +214,7 @@ namespace Avalonia.Controls
                 _nodeDic.Clear();
             }
 
-            public void Reset() => _nodeDic.Values.Do(node => node.Reset());
+            public void Reset(bool clearPos = true) => _nodeDic.Values.Do(node => node.Reset(clearPos));
 
             public GraphNode? AddLink(GraphNode from, Layoutable? to)
             {
@@ -255,28 +260,21 @@ namespace Avalonia.Controls
 
                 foreach (var node in nodes)
                 {
-                    /*
-                     * 该节点无任何依赖，所以从这里开始计算元素位置。
-                     * 因为无任何依赖，所以忽略同级元素
-                     */
                     if (!node.Measured && !node.OutgoingNodes.Any())
                     {
                         MeasureChild(node);
                         continue;
                     }
-
-                    //  判断依赖元素是否全部排列完毕
+                    
                     if (node.OutgoingNodes.All(item => item.Measured))
                     {
                         MeasureChild(node);
                         continue;
                     }
-
-                    //  判断是否有循环
+                    
                     if (!set.Add(node.Element))
                         throw new Exception("RelativePanel error: Circular dependency detected. Layout could not complete.");
-
-                    //  没有循环，且有依赖，则继续往下
+                    
                     Measure(node.OutgoingNodes, set);
 
                     if (!node.Measured)

src/Avalonia.Controls/Remote/Server/RemoteServerTopLevelImpl.cs

@@ -192,7 +192,7 @@ namespace Avalonia.Controls.Remote.Server
                             GetAvaloniaInputModifiers(pressed.Modifiers)));
                     }, DispatcherPriority.Input);
                 }
-                if (obj is PointerPressedEventMessage released)
+                if (obj is PointerReleasedEventMessage released)
                 {
                     Dispatcher.UIThread.Post(() =>
                     {

src/Avalonia.Controls/ToolTipService.cs

@@ -28,14 +28,22 @@ namespace Avalonia.Controls
             {
                 control.PointerEnter -= ControlPointerEnter;
                 control.PointerLeave -= ControlPointerLeave;
+                control.DetachedFromVisualTree -= ControlDetaching;
             }
 
             if (e.NewValue != null)
             {
                 control.PointerEnter += ControlPointerEnter;
                 control.PointerLeave += ControlPointerLeave;
+                control.DetachedFromVisualTree += ControlDetaching;
             }
         }
+        
+        private void ControlDetaching(object sender, VisualTreeAttachmentEventArgs e)
+        {
+            var control = (Control)sender;
+            Close(control);
+        }
 
         /// <summary>
         /// Called when the pointer enters a control with an attached tooltip.

src/Avalonia.FreeDesktop/DBusHelper.cs

@@ -43,7 +43,7 @@ namespace Avalonia.FreeDesktop
             public void Initialized()
             {
                 lock (_lock)
-                    _ctx = new AvaloniaSynchronizationContext();
+                    _ctx = new AvaloniaSynchronizationContext(null);
             }
         }
         public static Connection Connection { get; private set; }

src/Windows/Avalonia.Win32/Interop/UnmanagedMethods.cs

@@ -1,4 +1,5 @@
 using System;
+using System.ComponentModel;
 using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
@@ -1059,9 +1060,21 @@ namespace Avalonia.Win32.Interop
         [DllImport("user32.dll")]
         public static extern bool SetFocus(IntPtr hWnd);
         [DllImport("user32.dll")]
+        public static extern IntPtr GetFocus();
+        [DllImport("user32.dll")]
         public static extern bool SetParent(IntPtr hWnd, IntPtr hWndNewParent);
         [DllImport("user32.dll")]
         public static extern IntPtr GetParent(IntPtr hWnd);
+
+        public enum GetAncestorFlags
+        {
+            GA_PARENT = 1,
+            GA_ROOT = 2,
+            GA_ROOTOWNER = 3
+        }
+
+        [DllImport("user32.dll")]
+        public static extern IntPtr GetAncestor(IntPtr hwnd, GetAncestorFlags gaFlags);
         [DllImport("user32.dll")]
         public static extern bool ShowWindow(IntPtr hWnd, ShowWindowCommand nCmdShow);
 
@@ -1382,6 +1395,22 @@ namespace Avalonia.Win32.Interop
                 throw new Exception("RtlGetVersion failed!");
             }
         }
+        
+        [DllImport("kernel32", EntryPoint="WaitForMultipleObjectsEx", SetLastError = true, CharSet = CharSet.Auto)]
+        private static extern int IntWaitForMultipleObjectsEx(int nCount, IntPtr[] pHandles, bool bWaitAll, int dwMilliseconds, bool bAlertable);
+
+        public const int WAIT_FAILED = unchecked((int)0xFFFFFFFF);
+
+        internal static int WaitForMultipleObjectsEx(int nCount, IntPtr[] pHandles, bool bWaitAll, int dwMilliseconds, bool bAlertable)
+        {
+            int result = IntWaitForMultipleObjectsEx(nCount, pHandles, bWaitAll, dwMilliseconds, bAlertable);
+            if(result ==  WAIT_FAILED)
+            {
+                throw new Win32Exception();
+            }
+
+            return result;
+        }
 
         [DllImport("user32.dll")]
         internal static extern int SetWindowCompositionAttribute(IntPtr hwnd, ref WindowCompositionAttributeData data);

src/Windows/Avalonia.Win32/NonPumpingWaitProvider.cs

@@ -0,0 +1,15 @@
+using System;
+using Avalonia.Threading;
+using Avalonia.Win32.Interop;
+
+namespace Avalonia.Win32
+{
+    internal class NonPumpingWaitProvider : AvaloniaSynchronizationContext.INonPumpingPlatformWaitProvider
+    {
+        public int Wait(IntPtr[] waitHandles, bool waitAll, int millisecondsTimeout)
+        {
+            return UnmanagedMethods.WaitForMultipleObjectsEx(waitHandles.Length, waitHandles, waitAll,
+                millisecondsTimeout, false);
+        }
+    }
+}

src/Windows/Avalonia.Win32/PopupImpl.cs

@@ -7,6 +7,7 @@ namespace Avalonia.Win32
 {
     class PopupImpl : WindowImpl, IPopupImpl
     {
+        private readonly IWindowBaseImpl _parent;
         private bool _dropShadowHint = true;
         private Size? _maxAutoSize;
 
@@ -19,18 +20,25 @@ namespace Avalonia.Win32
         public override void Show()
         {
             UnmanagedMethods.ShowWindow(Handle.Handle, UnmanagedMethods.ShowWindowCommand.ShowNoActivate);
-            var parent = UnmanagedMethods.GetParent(Handle.Handle);
-            if (parent != IntPtr.Zero)
-            {
-                IntPtr nextParent = parent;
-                while (nextParent != IntPtr.Zero)
-                {
-                    parent = nextParent;
-                    nextParent = UnmanagedMethods.GetParent(parent);
-                }
 
-                UnmanagedMethods.SetFocus(parent);
+            // We need to steal focus if it's held by a child window of our toplevel window
+            var parent = _parent;
+            while(parent != null)
+            {
+                if(parent is PopupImpl pi)
+                   parent = pi._parent;
+                else
+                    break;
             }
+
+            if(parent == null)
+                return;
+
+            var focusOwner = UnmanagedMethods.GetFocus();
+            if (focusOwner != IntPtr.Zero &&
+                UnmanagedMethods.GetAncestor(focusOwner, UnmanagedMethods.GetAncestorFlags.GA_ROOT)
+                == parent.Handle.Handle)
+                UnmanagedMethods.SetFocus(parent.Handle.Handle);
         }
 
         protected override bool ShouldTakeFocusOnClick => false;
@@ -118,6 +126,7 @@ namespace Avalonia.Win32
 
         private PopupImpl(IWindowBaseImpl parent, bool dummy) : base()
         {
+            _parent = parent;
             PopupPositioner = new ManagedPopupPositioner(new ManagedPopupPositionerPopupImplHelper(parent, MoveResize));
         }
 

src/Windows/Avalonia.Win32/Win32Platform.cs

@@ -93,6 +93,7 @@ namespace Avalonia.Win32
                 .Bind<IWindowingPlatform>().ToConstant(s_instance)
                 .Bind<PlatformHotkeyConfiguration>().ToSingleton<PlatformHotkeyConfiguration>()
                 .Bind<IPlatformIconLoader>().ToConstant(s_instance)
+                .Bind<AvaloniaSynchronizationContext.INonPumpingPlatformWaitProvider>().ToConstant(new NonPumpingWaitProvider())
                 .Bind<IMountedVolumeInfoProvider>().ToConstant(new WindowsMountedVolumeInfoProvider());
 
             if (options.AllowEglInitialization)

tests/Avalonia.Controls.UnitTests/RelativePanelTests.cs

@@ -82,5 +82,55 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(new Rect(0, 0, 20, 20), target.Children[0].Bounds);
             Assert.Equal(new Rect(0, 20, 20, 20), target.Children[1].Bounds);
         }
+
+        [Fact]
+        public void LeftOf_Measures_Correctly()
+        {
+            var rect1 = new Rectangle { Height = 20, Width = 20 };
+            var rect2 = new Rectangle { Height = 20, Width = 20 };
+
+            var target = new RelativePanel
+            {
+                VerticalAlignment = Layout.VerticalAlignment.Center,
+                HorizontalAlignment = Layout.HorizontalAlignment.Center,
+                Children =
+                {
+                    rect1, rect2
+                }
+            };
+
+            RelativePanel.SetLeftOf(rect2, rect1);
+            target.Measure(new Size(400, 400));
+            target.Arrange(new Rect(target.DesiredSize));
+
+            Assert.Equal(new Size(20, 20), target.Bounds.Size);
+            Assert.Equal(new Rect(0, 0, 20, 20), target.Children[0].Bounds);
+            Assert.Equal(new Rect(-20, 0, 20, 20), target.Children[1].Bounds);
+        }
+
+        [Fact]
+        public void Above_Measures_Correctly()
+        {
+            var rect1 = new Rectangle { Height = 20, Width = 20 };
+            var rect2 = new Rectangle { Height = 20, Width = 20 };
+
+            var target = new RelativePanel
+            {
+                VerticalAlignment = Layout.VerticalAlignment.Center,
+                HorizontalAlignment = Layout.HorizontalAlignment.Center,
+                Children =
+                {
+                    rect1, rect2
+                }
+            };
+
+            RelativePanel.SetAbove(rect2, rect1);
+            target.Measure(new Size(400, 400));
+            target.Arrange(new Rect(target.DesiredSize));
+
+            Assert.Equal(new Size(20, 20), target.Bounds.Size);
+            Assert.Equal(new Rect(0, 0, 20, 20), target.Children[0].Bounds);
+            Assert.Equal(new Rect(0, -20, 20, 20), target.Children[1].Bounds);
+        }
     }
 }

tests/Avalonia.Controls.UnitTests/ToolTipTests.cs

@@ -30,6 +30,40 @@ namespace Avalonia.Controls.UnitTests
 
             Assert.False(ToolTip.GetIsOpen(control));
         }
+        
+        [Fact]
+        public void Should_Close_When_Control_Detaches()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var window = new Window();
+
+                var panel = new Panel();
+                
+                var target = new Decorator()
+                {
+                    [ToolTip.TipProperty] = "Tip",
+                    [ToolTip.ShowDelayProperty] = 0
+                };
+                
+                panel.Children.Add(target);
+
+                window.Content = panel;
+
+                window.ApplyTemplate();
+                window.Presenter.ApplyTemplate();
+
+                Assert.True((target as IVisual).IsAttachedToVisualTree);                               
+
+                _mouseHelper.Enter(target);
+
+                Assert.True(ToolTip.GetIsOpen(target));
+                
+                panel.Children.Remove(target);
+                
+                Assert.False(ToolTip.GetIsOpen(target));
+            }
+        }
 
         [Fact]
         public void Should_Open_On_Pointer_Enter()