Separate names with a comma.
I have same problems and tried to find what was the problem.
There was no problem using only one monitor, but I could not log in normally when...
When I checked "displays have separate spaces" at Mission Control of OSX (ver. 10.11.6), No problem was generated.
But, after uncheck "displays...
Also, I have same problem after Parallels 12 and hot fix 12.0.1-41296.
I can't use my external monitor at the same time on full screen mode.