Propertly handle an InlineUIContainer's logical children

src/Avalonia.Controls.DataGrid/DataGrid.cs

@@ -3979,7 +3979,7 @@ private void DataGrid_LostFocus(object sender, RoutedEventArgs e)
                     {
                         if (focusedObject is Control element)
                         {
-                            parent = element.Parent;
+                            parent = element.VisualParent;
                             if (parent != null)
                             {
                                 dataGridWillReceiveRoutedEvent = false;

src/Avalonia.Controls.DataGrid/Utils/TreeHelper.cs

@@ -36,7 +36,7 @@ internal static bool ContainsChild(this Visual element, Visual child)
                     {
                         if (child is Control childElement)
                         {
-                            parent = childElement.Parent;
+                            parent = childElement.VisualParent;
                         }
                     }
                     child = parent;

src/Avalonia.Controls/AutoCompleteBox/AutoCompleteBox.cs

@@ -792,7 +792,7 @@ protected bool HasFocus()
                     Control? element = focused as Control;
                     if (element != null)
                     {
-                        parent = element.Parent;
+                        parent = element.VisualParent;
                     }
                 }
                 focused = parent;

src/Avalonia.Controls/Control.cs

@@ -2,14 +2,12 @@
 using System.Collections.Generic;
 using System.ComponentModel;
 using Avalonia.Automation.Peers;
-using Avalonia.Controls.Documents;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
 using Avalonia.Input;
 using Avalonia.Input.Platform;
 using Avalonia.Interactivity;
 using Avalonia.LogicalTree;
-using Avalonia.Media;
 using Avalonia.Rendering;
 using Avalonia.Styling;
 using Avalonia.Threading;
@@ -211,8 +209,6 @@ public event EventHandler<SizeChangedEventArgs>? SizeChanged
             remove => RemoveHandler(SizeChangedEvent, value);
         }
 
-        public new Control? Parent => (Control?)base.Parent;
-
         /// <inheritdoc/>
         bool IDataTemplateHost.IsDataTemplatesInitialized => _dataTemplates != null;
 

src/Avalonia.Controls/Documents/InlineUIContainer.cs

@@ -64,5 +64,23 @@ internal override void BuildTextRun(IList<TextRun> textRuns)
         internal override void AppendText(StringBuilder stringBuilder)
         {
         }
+
+        protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
+        {
+            base.OnPropertyChanged(change);
+
+            if (change.Property == ChildProperty)
+            {
+                if(change.OldValue is Control oldChild)
+                {
+                    LogicalChildren.Remove(oldChild);
+                }
+
+                if(change.NewValue is Control newChild)
+                {
+                    LogicalChildren.Add(newChild);
+                }
+            }
+        }
     }
 }

src/Avalonia.Controls/Platform/DefaultMenuInteractionHandler.cs

@@ -553,7 +553,7 @@ protected void SelectItemAndAncestors(IMenuItem item)
             }
         }
 
-        protected static IMenuItem? GetMenuItem(Control? item)
+        protected static IMenuItem? GetMenuItem(StyledElement? item)
         {
             while (true)
             {

src/Avalonia.Controls/Primitives/OverlayPopupHost.cs

@@ -48,7 +48,7 @@ bool IPopupHost.Topmost
             set { /* Not currently supported in overlay popups */ }
         }
 
-        protected internal override Interactive? InteractiveParent => Parent;
+        protected internal override Interactive? InteractiveParent => (Interactive?)VisualParent;
 
         public void Dispose() => Hide();
 

src/Avalonia.Controls/Primitives/Popup.cs

@@ -723,7 +723,7 @@ private void CloseCore()
 
                     while (e is object && (!e.Focusable || !e.IsEffectivelyEnabled || !e.IsVisible))
                     {
-                        e = e.Parent;
+                        e = e.VisualParent as Control;
                     }
 
                     if (e is object)

src/Avalonia.Controls/Primitives/PopupRoot.cs

@@ -72,12 +72,12 @@ public Transform? Transform
         /// <remarks>
         /// Popup events are passed to their parent window. This facilitates this.
         /// </remarks>
-        protected internal override Interactive? InteractiveParent => Parent;
+        protected internal override Interactive? InteractiveParent => (Interactive?)Parent;
 
         /// <summary>
         /// Gets the control that is hosting the popup root.
         /// </summary>
-        Visual? IHostedVisualTreeRoot.Host => Parent;
+        Visual? IHostedVisualTreeRoot.Host => VisualParent;
 
         /// <summary>
         /// Gets the styling parent of the popup root.

src/Avalonia.Controls/ProgressBar.cs

@@ -231,7 +231,7 @@ protected override void OnApplyTemplate(TemplateAppliedEventArgs e)
         private void UpdateIndicator()
         {
             // Gets the size of the parent indicator container
-            var barSize = _indicator?.Parent?.Bounds.Size ?? Bounds.Size;
+            var barSize = _indicator?.VisualParent?.Bounds.Size ?? Bounds.Size;
 
             if (_indicator != null)
             {

src/Avalonia.Controls/TextBlock.cs

@@ -673,8 +673,6 @@ protected override Size MeasureOverride(Size availableSize)
                             controlRun.Control is Control control)
                         {
                             VisualChildren.Remove(control);
-
-                            LogicalChildren.Remove(control);
                         }
                     }
                 }
@@ -693,8 +691,6 @@ protected override Size MeasureOverride(Size availableSize)
                     {
                         VisualChildren.Add(control);
 
-                        LogicalChildren.Add(control);
-
                         control.Measure(Size.Infinity);
                     }
                 }