In order to disable XINERAMA, we can either:
Merely passing -rrxinerama will only disable the Randr-XINERAMA part, but the PanoramiX-XINERAMA implementation will stay enabled.
Also see https://github.com/ArcticaProject/nx-libs/blob/3.6.x/nx-X11/programs/Xserver... for more information.
Older nxagent versions do not support the xinerama nx/nx option or the -rrxinerama switch.
Mihai