protected override void OnKeyDown(KeyEventArgs e)
{
base.OnKeyDown(e);
if (!e.Handled)
{
RibbonHelper.HandleDropDownKeyDown(
this,
e,
delegate { return(IsOverflowOpen); },
delegate(bool value) { IsOverflowOpen = value; },
RetainFocusOnEscape ? _overflowButton : null,
_overflowPopup.TryGetChild());
}
}