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Yeah, I see that you lose the ability to drag and drop between displays on the OSX side. But I always use Magnet to move apps between displays...
I was in the same boat very frustrated but finally got it working as I expected to (...which I have to imagine is how some others here would,...
Just chiming in to confirm the same annoyances and grievances. I waited a while to upgrade to PD12 not knowing about these specific issues but...