private void OnDockspacePageDropDownClicked(object sender, CancelDropDownEventArgs e)
{
// Click the drop down button should cause the slide out to be focused so that it
// does not slide back again if you move the mouse away from the slide out area
if (_dockspaceSlide != null)
_dockspaceSlide.Select();
if (PageDropDownClicked != null)
PageDropDownClicked(sender, e);
}