protected override System.Windows.Size MeasureOverride(System.Windows.Size constraint) =>
 VerticalStackLayoutManager.Instance.MeasureOverride(this, constraint.ToStandardUISize()).ToWpfSize();
 protected override System.Windows.Size ArrangeOverride(System.Windows.Size arrangeSize) =>
 VerticalStackLayoutManager.Instance.ArrangeOverride(this, arrangeSize.ToStandardUISize()).ToWpfSize();