Here's an odd one, that I don't know if you can reproduce. I reboot. After it boots back up, I shut the screen off. I hit the home button. Screen comes on, with a Choose Android/System widget selector. Hit the back button or pick a widget and it goes away. I can't reproduce this frequently enough though. I have tried many combos. I have seen it happen 3 times though. I have no idea what is really causing it.