private void OnDismissPopup(RibbonDismissPopupEventArgs e)
{
if (e.DismissMode == RibbonDismissPopupMode.Always)
{
// Stop popup dismissal if the original source
// is from FilterPane.
ContentPresenter filterPane = FilterContentPane;
if (filterPane != null &&
RibbonHelper.IsAncestorOf(filterPane, e.OriginalSource as DependencyObject))
{
e.Handled = true;
}
}
}