it just means that the app is selected, like try to use the physical keyboard and the 4 way dpad and go from icon to icon on the home screen and you will see
i am using panda home and having the same problem...every time I wake up the phone one icon on the page is highlighted...not just sometimes every time. usually the second row from top and far left but appears always and in a different spot if on a different home page...annoying but not affecting performance..I do have replacement icons thru better cut...any help with eliminating this