I have both the 22" and 23" Apple Cinema Displays and after repositioning them I have noticed that they are starting to form these black spots around the usb ports on the back of the display which to me looks like dust but I really cant tell, Is this a cause for concern or are these spots something I'm going to have to live with. I've had the 22" for bout 1 year and the 23" for bout 9 months.