Hey all, So recently my macbook pro has been exhibiting some odd behavior. I have the mid-2012 i7 2.9 model (HD4000). It's on 10.9.2 and I've taken absolutely wonderful care of it. However, over the past couple of weeks, when connected to an external monitor at 1920x1080 and when woken from sleep, odd vertical lines will appear across the screen. Also, the external display will have some flickering. I know this isn't a problem with the monitor since I've tried it on several external monitors (one of which was new of the box.) The flickering comes and goes, but to get rid of the vertical lines I have to pull out the thunderbolt display adapter and plug it back in, It occurs on both VGA and HDMI. Do you think this is a problem with my thunderbolt port or with the logic board itself? When I'm home from school I'm going to make an appointment at the apple store. I have apple care.