The screen calibration seems to be a little off or something? The knock on feature barely works to wake it up but works flawlessly to put it to sleep. Also, when I try to scroll the screen from the bottom towards the top, it just wants to select whatever my finger landed on to swipe, then I have to hit the back button. Sometimes this goes on and on and is extrememly annoying. Both of these problems were not even a hint of being there on the one I played with in the store so I'm sure it's a fluke thing, that's my luck. Have y'all had any of these problems? Anything I can do to fix it so I don't have to return it?