public override void OnApplyTemplate()
{
CoerceValue(ControlSizeDefinitionProperty);
base.OnApplyTemplate();
PropertyHelper.TransferProperty(this, ContextMenuProperty); // Coerce to get a default ContextMenu if none has been specified.
PropertyHelper.TransferProperty(this, RibbonControlService.CanAddToQuickAccessToolBarDirectlyProperty);
_contentHost = GetTemplateChild(ContentHostTemplatePartName) as ScrollViewer;
TemplateApplied = true;
}