My Macbook Air is acting up...\n\nI have an iMac which I've used as a displayport monitor in the past\nwith a Macbook Pro, and decided I'd do it again now with my Macbook\nAir (4,2 - mid 2011) which has a thunderbolt connector. My iMac only\nhas a displayport connector.\n\nI've managed to make it work a couple of times, but most of the times,\nit doesn't. I hit cmd-F2 and the iMac screen blanks out but then comes\nback to the iMac screen again. I've tried restarting both machines,\nrunning lid open and lid closed (when I do get it working with lid\nopen, there is a lot of flickering).\n\nThis reminds me of a problem I had with my Windows PC a long time ago,\nwhere it worked after I switched cables. So I tried another cable but\nit's the same thing.\n\nI tried to connect the Macbook Air to my Dell monitor as well, but it\ndidn't work any better. Manage to get dual monitor image once, but\nthen I lost it.\n\nThe cables I use are Deltacos and some non-branded ones. Do I need to\nget Apple cables? I know that these cables worked flawlessly with my\nMacbook Pro on both the iMac and the Dell monitor a year ago.\n\nAny ideas?