I just got one of the new 13in macbooks. It's the solid aluminum case with a white apple logo on the backside of the screen. One day when I opened it up and the apple logo illuminated, I noticed a little gray spot in the lower center of it. Do any of you know what could be causing this or have had this happen to you before? The outside is damaged in no way, the logo is still perfectly smooth and everything, so I have no idea. Any help is greatly appreciated. Thanks.