diff --git a/tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs b/tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs
index 783215fb5d..c8a30a42e9 100644
--- a/tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/ComboBoxTests.cs
@@ -40,6 +40,7 @@ namespace Avalonia.Controls.UnitTests
                 Items = items,
                 SelectedIndex = 0,
             };
+            var root = new TestRoot(target);
 
             var rectangle = target.GetValue(ComboBox.SelectionBoxItemProperty) as Rectangle;
             Assert.NotNull(rectangle);