Hello everyone!

I've this weird problems on my ubuntu 12.04.2 machine with gnome-shell 3.4, gnome3 PPA and some backports from quantal:

gksudo doesn't work anymore and it just says "cannot open display" when I try "gksudo gedit", but if I try "gksudo nautilus" it just silently fails. same for almost every other GUI programs.
If I do "sudo su" and then "nautilus" same behaviour.
pkexec works smoothly
echo DISPLAY says :0
under unity same behaviour
already checked forums allaround

I didn't change anything manually in the recent period but a "normal" upgrade changed all the xorg packages under the rule of the xserver-xorg-renamed so all of these packages now has a -lts-quantal in their names. I can't confirm if the issue appear in that moment.

Aside from that I can't install extensions from the website with any browser and I don't know if the issues are realted.

thanks to anyone who can help