Desktop upside down

[Valerio Pachera]

Hi all, here I have a strange problem, always on edubuntu 12.04 + kde.
In the lab I'm managing there are old pc and 6 "new" pc.
If I activate desktop effects form kde and I log into one of the new
pc, everything goes up side down!
What I didn't aspect is that, logging out from kde and going into
gnome, the desktop is still upside down!

Do gnome and kde share compiz or something?

Disabling desktop effects everything goes fine.

Ha anybody else experienced something similiar?
I found other people on internet having this problem but not a clear
cause or solution.