System Preferences -> Desktop is kind of broken

[MyFakeAcc]

Hi.
I got some problems. Before upgrading to 10.8 I added two folders (let's say A and B). These folders are now not removable for me. I click the "-" and they disappear but once System Preferences is relaunched they are present again.

System Preferences[707]: Could not restore selection, using default folder

Is listed in Console.app for every time I remove A or B.

I already deleted the corresponding .plists:
~/Library/Preferences/com.apple.desktop.plist
~/Library/Preferences/com.apple.systempreferences.plist
~/Library/Preferences/ByHost/com.apple.screensaver.*

But after a restart of Sys Prefs the files reappear - with entries for folder A and B! There has to be some default setting for SysPrefs but I don't know where. Even editing the plist files directly and changing the values will be ignored. Adding a new folder works but only the last one added persists (others disappear).

I tried starting System Preferences as root for the case there would be some missing write permissions but without success. I got no clue what to do next. :/

Whenever I change ~/Library/Preferences/com.apple.desktop.plist it will be overriden when System preferences is relaunched. Removing rw permissions for everyone editing the .plist by hand does not help, too. The changes will be ignored.

 

[MyFakeAcc]

Seems like I was able to track down the problem but still no fix.
Whenever I change some folders in 'Desktop' preferences those changes apply to a record '0' in com.apple.desktop.plist. (Root -> Background -> spaces -> 0) while the values are loaded from records '458607821' and '722488972' (my two attached displays). Console logs the following:

07.10.12 13:16:32,810 Dock[340]: DesktopPicture: sent notification for space  and display 0x0 that does not exist

So the changes are applied to the wrong record.

I plugged in/out my displays multiple times as well as rearranged them but still no luck.