Can't change wallpaper in 10.8
I'm running 10.8 and at the upgrade I've been unable to change my desktop picture. I've repaired Permissions several times with no luck. The new wallpaper shows up in the Menu Bar but nothing else changes. The only time I can see the newly selected wallpaper is when I'm in Launchpad. Any thoughts?? Thanks.
Mac Pro, Mac OS X (10.7.4), Xserve 10.5.8 and ARD 3.6