Possible Duplicate: Gnome Shell Extension Empty I just upgraded to Ubuntu 12.4 running on a Win 7 box via VBox and switched the user interface to Gnome 3 but have a problem. In Advanced Settings (gnome tweak), the Shell Extensions window has no listings and the Theme window shows a "caution" triangle next to the Shell theme drop box. I have re-installed the default extensions using the Noobs Lab posted instructions: sudo apt-get install shell-extensions3.4 sudo apt-get install gnome-shell-extensions The commands appear to complete without error. Symptoms are: Gnome 2 visual appearance and no window borders or controls. To close a window, I have to click the window indicator in the sys tray and select the close menu item. Any ideas?