private void OnLostMouseCaptureThunk(MouseEventArgs e)
{
UIElement popupChild = _overflowPopup.TryGetChild();
RibbonHelper.HandleLostMouseCapture(
this,
e,
delegate() { return(IsOverflowOpen && !InContextMenu); },
delegate(bool value) { IsOverflowOpen = value; },
popupChild,
popupChild);
}