I've been testing out the adb shell am display-size and adb shell am display-density on my 10 inch tablet using the command prompt. The adb shell am display-density is considered an unrecognized command while adb shell am display-size, I was able to change the display size to 800x500 but not to 1280x800 (7 inch display size?). I want to test an Android app I created on a 7 inch display size. Also, the three buttons on the bottom where the home/back key is disappears. They won't reappear even when I do adb shell am display-size reset. The only way to get the keys back are by restarting the whole system. How can I fix these problems?