Hey guys - I have a question about hooking up a second display to my macbook air 2012. When I use it as a secondary monitor (not mirrored), I can only fullscreen an application on the macbook screen. If I drag the window to the second monitor and click full screen, it goes back to the MBA screen and just leaves the gray mesh background on the secondary monitor. What gives? Is there a way to fix this? Why would they do this?