title: Controls on Pivot disappear
body: <p>I have an app with a pivot control. The pivot control has two items (pages), both contain a <code>grid</code>. The grids contain a few buttons and one a map and the other a text block. When the app first runs the pivot works as expected. However, after the app has been running some time, like a day, all the controls on the pivot disappear after pivoting (or swiping). They appear momentarily while swiping, but disappear again once the pivot rests. </p>
  
  <p>Has anyone else experienced this? What could be the cause and solution?</p>
  
  <p>Video: <a href="http://www.youtube.com/watch?v=nd7bfTJ53Nk">http://www.youtube.com/watch?v=nd7bfTJ53Nk</a></p>
  
  <p>Code: <a href="https://github.com/JamieKitson/TrackLog/">https://github.com/JamieKitson/TrackLog/</a></p>