Hello everyone! For a week now I've been having an odd problem: I close my MacBook Pro when I'm not using it and every time I open it, the screen is full of white horizontal lines. On the upper half of the screen there are none to very few, but they get more around the middle and the lowest quarter of the screen is completely white with them. They don't disappear on their own, but after clicking here and there a few times, they suddenly disappear. Is this something to worry about? Where does it come from? I hope you can help me!!