I've got a late 2013 rMBP, and I'm having a strange issue with my Thunderbolt/DisplayPort port. When I move the computer when my external is plugged in, my external disconnects and goes black. Basically, the DisplayPort cable seems to be getting moved around, and the same thing happens when I press down lightly on the DisplayPort plug when it's connected to my laptop. Do others have this issue? When you move the DisplayPort plug up and down or move your laptop when it's plugged in, does it have this issue? I don't remember seeing this before and I don't know if it's my laptop or the cable or something else.