Office 2010 Ribbon - Windows 7 menu query

I've created an application using the TMS Office 2010 ribbon application template and trying to understand a functional difference between the two modes. When using the ribbon toolbar (TAdvToolBarPager) when it is set to be Windows 7 style the application button uses the TAdvPreviewMenu object that is on the page (which has to have menu items added) vs Office 2010 style the application button shows the frame as the menu to select from.

Is there a reason why there is this functional difference? (Switching between Windows 7 and Office styles doesn't happen easily in that case). Also the menu doesn't have access to the GDIPictureContainer so presumably has to use a normal ImageList to populate images.

Thanks for any clarification you can give.