
<ribbon:Ribbon>
<ribbon:Ribbon.ApplicationMenu>
<ribbon:ApplicationMenu MinHeight="200">
<ribbon:PopupButton ImageSourceLarge="/Res/About32.ico" ImageSourceSmall="/Res/About16.ico" Label="Another Sub-menu" KeyTipAccessText="S">
<ribbon:Menu ItemVariantSize="Medium">
<ribbon:Separator Label="Sub-Menu Header Label" />
<ribbon:Button IsChecked="True" ImageSourceLarge="/Res/About32.ico" ImageSourceSmall="/Res/About16.ico" Label="Item 1" KeyTipAccessText="X"/>
<ribbon:Button ImageSourceLarge="/Res/About32.ico" ImageSourceSmall="/Res/About16.ico" Label="Item 2" KeyTipAccessText="C" />
<ribbon:Button ImageSourceLarge="/Res/About32.ico" ImageSourceSmall="/Res/About16.ico" Label="Item 3" KeyTipAccessText="P"/>
</ribbon:Menu>
</ribbon:PopupButton>
</ribbon:ApplicationMenu>
</ribbon:Ribbon.ApplicationMenu>
</ribbon:Ribbon>
How can I make the checked ribbon:Button to have the tick on the right end of the menu?