Hi guys, I'm running OS X Mavericks on my 2011 MacBook Pro. For about the last month or so, i've noticed an odd behaviour - my whole screen flashes at random times, though more recently, I've noticed that it flashes during certain behaviour. When I have the Twitter app for Mac OS open and click on any number buttons or letters, the screen seems to flash. I've uploaded a quick video on Youtube to show what happens: http://youtu.be/v9DY9FMntSQ I've also noticed this happen when I have the UTorrent app open - when the download completes and a growl notification is displayed on the top right of the screen to say that a download is complete, the screen also flashes. Does anyone have any idea on what is going on? I am seriously hoping that this is not a graphics card problem (after hearing of the common faulty graphics cards across the 2011 MBP line, i've been getting very paranoid) but rather something to do with OS X Mavericks instead or software related (which I can live with). Would appreciate any help and advice. Thank you!