Appearance prefs 'reset' after about 30 seconds

[Robert Spanjaard]

When I start my computer, Ubuntu 10.04 boots just fine. But about 30 
seconds after my desktop appears, the appearance goes from this...

http://www.arumes.com/temp/S1.png

...to this...

http://www.arumes.com/temp/S2.png

As soon as I start Prefs/Appearance, most of the settings are restored 
without setting anything. Running the Appearance program is enough to 
restore most. Nautilus (and the right-click menu on the desktop) seems to 
be the only exception; it doesn't change back to the appearance I 
selected, but stays in the looks of the second screenshot.

It's 10.04, 64 bits, proprietary ATI driver, and visual effects are all 
switched off. I didn't have this problem with 9.10, and I don't have the 
problem with 10.04 NE on my netbook.

-- 
Regards, Robert                                      http://www.arumes.com