not heard that one b4 but this
not heard that one b4 but this is what I would try.
disabling the NV xinerama info, this is taken from the readme
Option "NoTwinViewXineramaInfo" "boolean"
When in TwinView, the NVIDIA X driver normally provides
a Xinerama extension that X clients (such as window
managers) can use to to discover the current TwinView
configuration. Some window mangers can get confused by
this information, so this option is provided to disable
this behavior. Default: TwinView Xinerama information