Shahar's idea may work for unity users but removing metacity removes gnome-fallback i.e. the classic interface. Reinstalling it makes everything appear as it was (phew) but alt-tab goes back to not working.
Shahar's idea may work for unity users but removing metacity removes gnome-fallback i.e. the classic interface. Reinstalling it makes everything appear as it was (phew) but alt-tab goes back to not working.