title: Keyboard extension works in simulator but not on device
body: <p>I am developing custom keyboard extension. It worked fine in both simulator and device until now. </p>
  
  <p>After some small changes (adding <code>import AudioToolbox</code> in one class and one command) it suddenly stopped working on the device. The app compiles and runs but then I acivate my keyboard XCode shows following error:</p>
  
  <pre><code>Lost connection to "My iPhone".
  Restore the connection to "My iPhone" and run "xxx.xxx.xxx.xxx-Keyboard" 
  again, or if "xxx.xxx.xxx.xxx-Keyboard" is still running, you can 
  attach to it by selecting Debug &gt; Attach to Process &gt; xxx.xxx.xxx.xxx-Keyboard.
  </code></pre>
  
  <p>This error looks like the one that appears when iPhone cable is unplagged but the cable is all right in this case.</p>
  
  <p>My keyboard itself is not launched - when activated (using globe key) there is few seconds delay (which is normal when my keyboard is loading in debug) and then the previously active keyboard is shown.</p>
  
  <p>There are month of development in that project and I am completely stack so any help is very much appreciated. </p>