A reply to the last post only...
Just adding here that the problem probably can be resolved by rebooting the host (maybe there's a need for rebooting guests as well).
All of the problems I saw here with using another external screen as normally especially after waking up the laptop from an OS X sleep now appear to be gone. The side effects, black bars, maximized screens dropping out of max mode into some sort of windowed mode, maximized VMs disappearing from the swipe list, etc..
Now after finally rebooting everything (host+guests) my problems appear to be gone. (Still waiting on the results of a few more OSX sleeps, but it looks like everything is back to normal now)
Hope this helps,
--
Wil
edit: Scratch that, wasn't patient enough. Happened again on the 3rd sleep, same same, problem is still there.