yep ! using 10.9Thats odd. Because the last time i saw that happen was in Mountain lion and Lion.
You using Mavericks?
I have it unchecked and it still happens.. even restarted and still 1 monitor turns greyMavericks turns the second monitor gray in fullscreen, when System Preferences>Mission Control>Displays have seperate spaces checkbox is not ticked.
Nope Apple doesn't have a setting that caters to your needs sorry.unchecked it to get rid of the menubar and the dock.. is there a way to get rid of these while its checked?