Fix visual tree handling when Inlines is reset

src/Avalonia.Controls/TextBlock.cs

@@ -668,17 +668,7 @@ namespace Avalonia.Controls
 
             if (HasComplexContent)
             {
-                if (_textRuns != null)
-                {
-                    foreach (var textRun in _textRuns)
-                    {
-                        if (textRun is EmbeddedControlRun controlRun &&
-                            controlRun.Control is Control control)
-                        {
-                            VisualChildren.Remove(control);
-                        }
-                    }
-                }
+                VisualChildren.Clear();
 
                 var textRuns = new List<TextRun>();
 

tests/Avalonia.Controls.UnitTests/TextBlockTests.cs

@@ -115,6 +115,39 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
+        [Fact]
+        public void Changing_Inlines_Should_Reset_InlineUIContainer_VisualParent_On_Measure()
+        {
+            using (UnitTestApplication.Start(TestServices.MockPlatformRenderInterface))
+            {
+                var target = new TextBlock();
+
+                var control = new Control();
+
+                var run = new InlineUIContainer(control);
+
+                target.Inlines.Add(run);
+
+                target.Measure(Size.Infinity);
+
+                Assert.True(target.IsMeasureValid);
+
+                Assert.Equal(target, control.VisualParent);
+
+                target.Inlines = null;
+
+                Assert.Null(run.Parent);
+
+                target.Inlines = new InlineCollection { new Run("Hello World") };
+
+                Assert.Null(run.Parent);
+
+                target.Measure(Size.Infinity);
+
+                Assert.Null(control.VisualParent);
+            }
+        }
+
         [Fact]
         public void InlineUIContainer_Child_Schould_Be_Arranged()
         {