weird fullscreen problem MAC

Hi guys!!

I’ve got a macbook (late 2009 edition) and I attached a projector as a second screen. I realized that If I go fullscreen with mirroring monitors activated in the display preferences, I get my principal screen (macbook screen) broken in a lot of colors and weird graphics, and I only be able to see the application in the projector, in addition I can only fix the monitor of my macbook if I unplug the display port connector.

it goes Ok if I use extended display option in glut display and mirroring turned off in mac preferences.

Anyone has the same problem?? I tried with another friend’s macbook and the same thing happens.

Thanks!

update:

only happens with macbooks (not mackbook pros)