There is a set of commits done by LyonJack in VS2013 theme and in particular Generic.xaml that I don't really like. The default style for MenuItem and some other control types is changed which effectively is applied to any control that is inside the layout. Although I can't give ready solution right now I do believe it should be done in less intrusive way. Maybe use explicit style keys that are applied only to menu items in layout related XAML files.