title: How to disable key preview in popup keyboard (not in main softkeyboard layout)?
body: <p>It's easy to disable key previews: just call setPreviewEnabled(false) and these annoying tiny previews won't show up anymore. But if I attach a popup keyboard to any key then these previews will show up inside that popup:</p>
  
  <p>qwerty.xml:</p>
  
  <pre><code>&lt;Key android:codes="101" 
      android:keyLabel="E" 
      android:popupKeyboard="@xml/popup"
     android:keyTextSize="60sp"/&gt;
  </code></pre>
  
  <p>popup.xml:</p>
  
  <pre><code>&lt;Row&gt;
      &lt;Key android:codes="-10000"
          android:keyLabel="test"
          android:keyOutputText="test"/&gt;
  &lt;/Row&gt;
  &lt;Row&gt;
      &lt;Key android:codes="-10001"
          android:keyLabel="test2"
          android:keyOutputText="test2"/&gt;
  &lt;/Row&gt;
  </code></pre>
  
  <p>Can't post images, but if I long press letter 'E' and then press test or test2 button they will show that white key preview.</p>
  
  <p>Is there any way to disable these key previews too?</p>