[GDM: Xinerama] turned off, but GDM still unscaled

[pathfinder]

Hi guys,

A weird problem here.
I was using xinerama with 2 screens.
ATI crappy drivers and dodgy compiz fusion and a bad econdary screen made me forget this: I wanted to go back to the single screen set up, i.e. without xinerama.

Then I -xinerama in my make.conf and checked whether this flag was turned on in one of the package.X files: it was ok.
Then I emerged -auvDN world and revdep rebuild.

Everything was ok EXCEPT my GDM: it still streched to 2 screens, and as the second screen is OUT, I can t see the login field, neither the password field, neither the Session Chooser.. etc... I just see the left part of a 1280x1024 image stretched to 2560-1024...
How can I solve this?
It s weird, I did that lots of time, and i never had this issue...

edit:
i reemerged gdm... no changes.
i checked my xorg.conf, there was a line with # Option "DesktopSetup" "horizontal": I commented it, nothing changed...
Now re emerging with the latest ATI drivers (8.493)

[pathfinder]

ok.
the Brand New ATI Drivers are crap
my system couldn t launch the DM.
It bugged completely.
only GDM was ok. then, glitching, screen off, nothing... had to recover the previous ones.