Comment 136 for bug 160264

I don't think this bug has much to do with compiz or nvidia. I have the same bug on my 8.04, on a ThinkPad X60s, with xserver-xorg-video-intel.

What I found is that the bug can be reproduced simply by starting X (no gnome, no compiz, nothing) on two terminals like: X :0 vt7 and X :1 vt9. Now, when I switch to vt7, I see the blank screen with the cursor. However, if I start a third X server with X :2 vt10, I can switch between the second and the third one (vt9 and vt10).

So now, if I stop gdm, start one 'placeholder' X on vt7, then start gdm, I can work normally and do fast user switching from gnome, as only the first, 'dummy' X server is broken.