Stupid question but today I was working and all of a sudden a transparent rectangle appeared on the screen. It followed the curser. Right clicking didn't seem to do anything. Didn't seem to be software specific. I have two screens and it followed the curser from screen to screen. Didn't interfere with function. I restarted the computer which got rid of it. I'm sure I hit some key combination by accident, but I have no idea what I did or what the rectangle was intended to do. Anyone have any suggestions? Thanks.