Fix ListBoxItem visual state stuck when parent ListBox gains/loses focus

src/Tedd.TUI.Tests/ListBoxTests.cs

@@ -80,6 +80,66 @@ public void Render_UsesItemTemplate_WhenSet()
         Assert.Equal("Bob", row1);
     }
 
+    [Fact]
+    public void OnGotFocus_UpdatesSelectedItemVisualState()
+    {
+        // Arrange
+        var window = new TuiWindow();
+        var listBox = new ListBox();
+        window.Content = listBox;
+        listBox.Items.Add("Item 1");
+        listBox.Items.Add("Item 2");
+        listBox.SelectedIndex = 0;
+        listBox.Measure(new Size(20, 5));
+        listBox.Arrange(new Rect(0, 0, 20, 5));
+
+        var container = listBox.ItemsPanelRoot?.Children[0] as ListBoxItem;
+        Assert.NotNull(container);
+        Assert.True(container.IsSelected);
+
+        // Before focus, item should show unfocused selection colors
+        listBox.OnLostFocus();
+        var unfocusedBg = container.Background;
+        var unfocusedFg = container.Foreground;
+
+        // Act: ListBox gains focus
+        listBox.OnGotFocus();
+
+        // Assert: selected item should now show focused selection colors
+        Assert.NotEqual(unfocusedBg, container.Background);
+        Assert.NotEqual(unfocusedFg, container.Foreground);
+        Assert.Equal(listBox.FocusedSelectionBackground, container.Background);
+        Assert.Equal(listBox.FocusedSelectionForeground, container.Foreground);
+    }
+
+    [Fact]
+    public void OnLostFocus_UpdatesSelectedItemVisualState()
+    {
+        // Arrange
+        var window = new TuiWindow();
+        var listBox = new ListBox();
+        window.Content = listBox;
+        listBox.Items.Add("Item 1");
+        listBox.Items.Add("Item 2");
+        listBox.SelectedIndex = 0;
+        listBox.Measure(new Size(20, 5));
+        listBox.Arrange(new Rect(0, 0, 20, 5));
+
+        var container = listBox.ItemsPanelRoot?.Children[0] as ListBoxItem;
+        Assert.NotNull(container);
+
+        // First give focus so item shows focused selection colors
+        listBox.OnGotFocus();
+        Assert.Equal(listBox.FocusedSelectionBackground, container.Background);
+
+        // Act: ListBox loses focus
+        listBox.OnLostFocus();
+
+        // Assert: selected item should now show unfocused selection colors (ShowSelection=true by default)
+        Assert.Equal(listBox.SelectionBackground, container.Background);
+        Assert.Equal(listBox.SelectionForeground, container.Foreground);
+    }
+
     [Fact]
     public void Render_FallsBackToGetItemText_WhenNoTemplate()
     {

src/Tedd.TUI/ListBox.cs

@@ -126,6 +126,30 @@ protected internal override void PrepareContainerForItemOverride(UIElement eleme
         }
     }
 
+    public override void OnGotFocus()
+    {
+        base.OnGotFocus();
+        NotifyContainersVisualStateChanged();
+    }
+
+    public override void OnLostFocus()
+    {
+        base.OnLostFocus();
+        NotifyContainersVisualStateChanged();
+    }
+
+    private void NotifyContainersVisualStateChanged()
+    {
+        if (ItemsPanelRoot != null)
+        {
+            for (int i = 0; i < ItemsPanelRoot.Children.Count; i++)
+            {
+                if (ItemsPanelRoot.Children[i] is ListBoxItem lbi)
+                    lbi.UpdateVisualState();
+            }
+        }
+    }
+
     public override void OnKeyDown(KeyEventArgs e)
     {
         base.OnKeyDown(e);

src/Tedd.TUI/ListBoxItem.cs

@@ -75,7 +75,7 @@ protected override void OnPropertyChanged(DependencyProperty dp)
         }
     }
 
-    private void UpdateVisualState()
+    internal void UpdateVisualState()
     {
         // Try to get colors from Parent ListBox if we are inside one.
         // If not, use defaults.