I have a situation that when I view a movie in either Qt or Itunes, the fie I am viewing will be on top, but the area "behind" that should be black will show a frame from an earlier video? If I reboot it is fixed until I view another movie then if it is a square video it will show a wide screen frame on the sides of the picture. It is very annoying. If I wiggle the cursor and get the toolbar or bottom bar back..it goes away momentarily. I have had som many problesm since upgrading to High Sierra, and getting rid of my OLD MacMini (with the cdplayer) This is a newer model. No cd. IT SUCKS. But like I said if I reboot it goes away, for about two plays. If its a wides screen then the "square" video frame shows on top and bottom, if the video is the square shape, then the offending fram is on the sides. It will be the same frame until I reboot. It gets them from the last video. I have seen NOTHING remotely like this online.