title: Firefox Extension: Showing + Hidding AutoCompleteRichResult
body: <p>Setting any of</p>
  
  <pre><code>document.getElementById('PopupAutoCompleteRichResult').setAttribute('hidden', true)                                         
  document.getElementById('PopupAutoCompleteRichResult').hidden = true
  document.getElementById('PopupAutoCompleteRichResult').setAttribute('style', 'display: none;');`
  </code></pre>
  
  <p>hides the AutoComplete Popup.</p>
  
  <p>But how do I show it again? Neither <code>display: -moz-popup</code> nor <code>hidden = false</code> works!</p>