title: setSystemUIVsibility full screen disables when using Spinner
body: <p>I am using </p>
  
  <pre><code>View root = findViewById(android.R.id.content);
  root.setSystemUiVisibility(View.SYSTEM_UI_FLAG_FULLSCREEN);
  </code></pre>
  
  <p>to make my app full screen. It works fine, except when I use a <code>Spinner</code>. As soon as I dropdown the options, the system bar appears again. I tried using <code>setSystemUIVisibility()</code> on the <code>Spinner</code> to no effect.</p>
  
  <p>How can I get my app to be full screen all the time?</p>