fix: ChatBox Attchment Overlay bugs

1. overlay sometimes may not disappear
2. overlay will cover the ChatFloatingWindow

Author: DearVa

src/Everywhere/Views/Controls/ChatInputBox.axaml.cs

@@ -1,4 +1,5 @@
 using System.Collections.ObjectModel;
+using System.Collections.Specialized;
 using Avalonia.Controls;
 using Avalonia.Controls.Metadata;
 using Avalonia.Controls.Primitives;
@@ -210,6 +211,41 @@ protected override void OnApplyTemplate(TemplateAppliedEventArgs e)
             handledEventsToo: true);
     }
 
+    protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
+    {
+        base.OnPropertyChanged(change);
+
+        if (change.Property == ChatAttachmentItemsSourceProperty)
+        {
+            if (change.OldValue is INotifyCollectionChanged oldValue)
+            {
+                oldValue.CollectionChanged -= HandleChatAttachmentItemsSourceChanged;
+            }
+            if (change.NewValue is INotifyCollectionChanged newValue)
+            {
+                newValue.CollectionChanged += HandleChatAttachmentItemsSourceChanged;
+            }
+        }
+    }
+
+    private void HandleChatAttachmentItemsSourceChanged(object? sender, NotifyCollectionChangedEventArgs e)
+    {
+        if (_visualElementAttachmentOverlayWindow.IsValueCreated)
+        {
+            _visualElementAttachmentOverlayWindow.Value.UpdateForVisualElement(null); // Hide the overlay window when the attachment list changes.
+        }
+    }
+
+    protected override void OnUnloaded(RoutedEventArgs e)
+    {
+        base.OnUnloaded(e);
+
+        if (_visualElementAttachmentOverlayWindow.IsValueCreated)
+        {
+            _visualElementAttachmentOverlayWindow.Value.UpdateForVisualElement(null); // Hide the overlay window when the control is unloaded.
+        }
+    }
+
     protected override void OnPointerPressed(PointerPressedEventArgs e)
     {
         // Because this control is inherited from TextBox, it will receive pointer events and broke the MenuItem's pointer events.

src/Everywhere/Views/Windows/OverlayWindow.cs

@@ -4,10 +4,11 @@ namespace Everywhere.Views;
 
 public class OverlayWindow : Window
 {
-    // todo: make this window don't cover the owner
+    private readonly WindowBase? _owner;
+
     public OverlayWindow(WindowBase? owner = null)
     {
-        Owner = owner;
+        _owner = owner;
 
         CanResize = false;
         ShowInTaskbar = false;
@@ -41,6 +42,12 @@ public void UpdateForVisualElement(IVisualElement? element)
             var scaling = DesktopScaling;
             Width = boundingRectangle.Width / scaling;
             Height = boundingRectangle.Height / scaling;
+
+            if (_owner is { Topmost: true })
+            {
+                _owner.Topmost = false;
+                _owner.Topmost = true;
+            }
         }
     }
 }