I think Poser12 is definitely incompatible seeing as it is unusable for dual-monitor setups (unless it's just my iMac and Apple Thunderbolt monitor setup of course).

I can't change a texture in the material room, for example - the popup dialog is invisible and unfixable no matter what I do so I have to force-quit the application or unplug the second monitor.

Personally, I have no issues with Poser 11.

Poser 12 is a whole new world of pain for dual monitors.