feat: add remove command support.

src/Ursa/Controls/ComboBox/MultiComboBoxSelectedItemList.cs

@@ -0,0 +1,36 @@
+using System.Windows.Input;
+using Avalonia;
+using Avalonia.Controls;
+
+namespace Ursa.Controls;
+
+public class MultiComboBoxSelectedItemList: ItemsControl
+{
+    public static readonly StyledProperty<ICommand?> RemoveCommandProperty = AvaloniaProperty.Register<MultiComboBoxSelectedItemList, ICommand?>(
+        nameof(RemoveCommand));
+
+    public ICommand? RemoveCommand
+    {
+        get => GetValue(RemoveCommandProperty);
+        set => SetValue(RemoveCommandProperty, value);
+    }
+    
+    protected override bool NeedsContainerOverride(object? item, int index, out object? recycleKey)
+    {
+        return NeedsContainer<ClosableTag>(item, out recycleKey);
+    }
+
+    protected override Control CreateContainerForItemOverride(object? item, int index, object? recycleKey)
+    {
+        return new ClosableTag();
+    }
+
+    protected override void PrepareContainerForItemOverride(Control container, object? item, int index)
+    {
+        base.PrepareContainerForItemOverride(container, item, index);
+        if (container is ClosableTag tag)
+        {
+            tag.Command = RemoveCommand;
+        }
+    }
+}