title: Navbar overlaps game UI in Windows Phone
body: <p>I have a WP8 game that suddenly got an issue with WP8.1 devices that don't have hardware buttons: new navbar overlaps game, but all methods to determine screen size return correct size: 480x800, although it's obvious that it's drawn at 480x854.</p>
  
  <p>I've tried putting XAML elements over the screen and they are drawn properly (not overlapped), but they don't help because their coordinates can't help me to determine if screen has a navbar.</p>
  
  <p>How can a presence of a navbar be determined and how can an accurate rendering be done?</p>