any idea what's causing flickering in gnome when hitting activity button? please check out this: http://youtu.be/Q1HijRdeqUg
it seems like gnome is unable to compute the center of the screen - you can see the location of panel and also windows is a bit off. i am also seeing this with a newly created user - although it becomes an issue after a while, not straight after login.
arch is 32bit, nvidia proprietary drivers nvidia 337.12-1