fix: hack a default size.

demo/Ursa.Demo/ViewModels/MenuViewModel.cs

@@ -31,7 +31,7 @@ public class MenuViewModel: ViewModelBase
             new() { MenuHeader = "NumericUpDown", Key = MenuKeys.MenuKeyNumericUpDown, Status = "New" },
             new() { MenuHeader = "Pagination", Key = MenuKeys.MenuKeyPagination },
             new() { MenuHeader = "RangeSlider", Key = MenuKeys.MenuKeyRangeSlider, Status = "New"},
-            new() { MenuHeader = "Selection LIst", Key = MenuKeys.MenuKeySelectionList, Status = "New" },
+            new() { MenuHeader = "Selection List", Key = MenuKeys.MenuKeySelectionList, Status = "New" },
             new() { MenuHeader = "TagInput", Key = MenuKeys.MenuKeyTagInput },
             new() { MenuHeader = "Theme Toggler", Key = MenuKeys.MenuKeyThemeToggler },
             new() { MenuHeader = "Timeline", Key = MenuKeys.MenuKeyTimeline, Status = "Updated" },

src/Ursa/Controls/SelectionList/SelectionList.cs

@@ -70,6 +70,11 @@ public class SelectionList: SelectingItemsControl
             if (container is null) return size;
             _indicator.Arrange(container.Bounds);
         }
+        else
+        {
+            // This is a hack. The indicator is not visible, so we arrange it to a 1x1 rectangle
+            _indicator?.Arrange(new Rect(new Point(), new Size(1, 1)));
+        }
         return size;
     }