In previous similar situations Mesa was the culprit. A recent patch for Mesa has fixed things for some people, are you running the latest?
Running latest from git for libdrm, ddx, mesa and kernel.
OK, thanks for checking.
Are you still seeing this problem?
Yes. And I use the latest git mesa, drm, ddx with kernel 3.8 on Archlinux 64.
OK, thanks for checking.
Is this still happening? Similar corruption problems were all addressed.
I'm not the only one who was experiencing this problem. (see https://bugs.freedesktop.org/show_bug.cgi?id=70675). However, as been proposed and it seems to work. I haven't tested it yet, I'll let you know as soon as possible if the proposed patch works.
I just tested the patch and it fixes the bug. So it is a driver bug, not a Steam bug. It can be closed.
Nothing extracted yet.
All the windows I've come across for now are displayed correctly, except for the one when I want to remove a library folder. This one shows garbage. I can quit it by pushing ESC or the space bar.
Using Archlinux, with mesa r600g on an AMD HD 6950 with Steam from Dec 19, 2012 @ 14:14:29.