title: UIDocumentInteractionController: "Open In" visible on iPhone but not on iPad - why?
body: <p>For testing purposes I wrote two apps:</p>
  
  <ul>
  <li>First one plays an MP3 file using <code>UIDocumentInteractionController</code></li>
  <li>Second one does nothing but registers for the file type "<em>public.mp3</em>"</li>
  </ul>
  
  <p>If I deploy the apps to the <strong>iPhone</strong> Simulator, my MP3 player app shows a button on top "<em>Open in 'MP3Test'</em>". If I deploy to the <strong>iPad</strong> Simulator however, there is no button and no "Open In" menu either.</p>
  
  <p>This has been tested with iOS5.</p>
  
  <p>Can somebody explain if this is a bug or a feature and what the reason is behind it?</p>