This behavior happens in full screen mode, AKA Display View (Command-3). Several related things happen:
1. The control bar will disappear *immediately* when clicking on the timeline to scrub to a different spot in the video that's being played.
2. The control bar will not appear when moving the pointer to the top or side of the screen. Moving all the way to the bottom of the screen and then back to the top resets it.
3. The mouse pointer disappears entirely. Moving all the way to the bottom and back makes it appear again. Note this carries over into Standard View. The pointer is entirely gone, but you can see interface elements lighting up as you pass over them. A full movement all the way to the bottom of the screen makes the pointer reappear.
4. Panes and lists "flash" bright white with every tiny scroll. If you scroll say 10 items down, you get (seemingly) 10 flashes, which makes the screen almost impossible to read until you stop scrolling. Note, if you are using a very bright white skin like Noire, the flashes are more subtle, as they are flashing more like dark gray.
You can induce #1 by skipping to the next video in Playing Now and then trying to scrub through the video.
#2 and 3 are hard to induce, but it happens with enough viewing. I'll post if I figure out an exact way to induce the behavior.
#4 happens *constantly*. Just play a video, scrub around in it a bit, and then return to a view with a list or Pane. You'll see the flashes. The only way to fix it is to restart MC.
These are all pretty annoying, but #4 makes it very hard to use MC and forces me to restart it fairly frequently.
Thanks,
Brian.