I believe you are out of luck. Poser underpinnings are rooted back in Windoze 3.1 or thereabouts, long before 2 displays were supported. And with CL's practice (if not policy) of add not fix, there have been no updates in this or similar areas - e.g. File Dialogs, Color Picker, yada, yada, ... (Wereas on Mac dual displays were added by Radius early, early, early on, and adopted by Apple, so were around when Poser got it's rootstock. The addition of dual displays on Mac was done right in the OS too, not in the drivers a la M$ ;-)