Hi: I have a Mid 2012 13" MBA (2 GHz Intel Core i7/ 8Gig Ram) running Yosemite with an external Dell Ultra Sharp U2715H 2560x1440 monitor. Everything is working fine but there's a 1/4" border around the outside of the LCD that shouldn't be there. I'm not talking about the monitor's black plastic bezel, but an area of black space that should be an active part of the LCD (see attached picture.) I spoke with Dell and they confirmed the LCD should be active all the way to the bezel. They also said the problem is probably with my graphics card which is an Intel HD Graphics 4000 with 1024 MB. I can live with this, but it would be nice to get the LCD to fire edge to edge and top to bottom. Does anyone have any suggestions beyond resetting the PRAM? Thanks for the help.