From de87609de1859e1c28fad65af4e233ff5a489bca Mon Sep 17 00:00:00 2001
From: Dan Walmsley <dan@walms.co.uk>
Date: Wed, 15 Jul 2020 13:32:06 -0300
Subject: [PATCH 1/2] add failing unit test.

---
 .../ToolTipTests.cs                           | 34 +++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/tests/Avalonia.Controls.UnitTests/ToolTipTests.cs b/tests/Avalonia.Controls.UnitTests/ToolTipTests.cs
index 34b37e7635..9d7bc6af74 100644
--- a/tests/Avalonia.Controls.UnitTests/ToolTipTests.cs
+++ b/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()

From a542d8753de026bd786c914b571c2a680a2ce77c Mon Sep 17 00:00:00 2001
From: Dan Walmsley <dan@walms.co.uk>
Date: Wed, 15 Jul 2020 13:33:20 -0300
Subject: [PATCH 2/2] ensure tooltips are closed when its parent detaches from
 visual tree.

---
 src/Avalonia.Controls/ToolTipService.cs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/Avalonia.Controls/ToolTipService.cs b/src/Avalonia.Controls/ToolTipService.cs
index d90729e8a5..569697304f 100644
--- a/src/Avalonia.Controls/ToolTipService.cs
+++ b/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.