GPO blocking display of IE9 tabs?

so i set a bunch of settings in GPO in Windows Server 2008 R2 for a Win7 computer, and now the tabbed browsing tabs are not showing up! you can still open a new tab, and the tabs are apparently there, but you cannot see them.

i did NOT disable anything as far as tabs were concerned, but i'm wondering if some GPO disables tabs as a by-product?