private void OnDismissPopup(RibbonDismissPopupEventArgs e)
{
UIElement popupChild = _overflowPopup.TryGetChild();
RibbonHelper.HandleDismissPopup(
e,
delegate(bool value) { IsOverflowOpen = value; },
delegate(DependencyObject d) { return(d == _overflowButton); },
popupChild,
this);
}