I'm running Parallels 8 on a 15" MBP and have a Win8 guest set to "Use All Displays in Full Screen" so that Windows can see both monitors. I am trying to set it up for a presentation where I want my Win8 desktop DUPLICATED on the external monitor, but when I go to the display settings in Win8 and choose "Duplicate these displays" it instantly changes my selection to "Show Desktop Only on 1" and asks me to apply. Similarly, if I do Windows-P to change presentation settings and select "Duplicate" it does nothing. It appears that there's no way to get a Win8 guest to duplicate the desktop across two monitors. Is this accurate and just a limitation of Parallels, or am I missing something?