title: QCompleter and QListWidget as custom popup issue
body: <p>I have a QCompleter using a QStringListModel for my QPlainTextEdit (<a href="http://qt-project.org/doc/qt-5.0/tools-customcompleter.html" rel="nofollow">check this example</a>):</p>
  
  <pre><code>  QStringListModel* model = new QStringListModel(names);
    QCompleter* completer = new QCompleter(model);
    completer-&gt;setCompletionMode(QCompleter::PopupCompletion);
    completer-&gt;setModelSorting(QCompleter::UnsortedModel);
  </code></pre>
  
  <p>It works fine. Now I need some Icon, Tooltips for each suggestion I'm trying to use a QListWidget as custom popup:</p>
  
  <pre><code>  QListWidget* w = new QListWidget();
    foreach(name, names) {
      QListWidgetItem* i = new QListWidgetItem(name);
      i-&gt;setIcon(/*my Icon*/);
      i-&gt;setToolTip("");
      w-&gt;addItem(i);
    }
    completer-&gt;setPopup(w);
  </code></pre>
  
  <p>The popup ok, just like I need, but the completion no more work. I cannot type the text to make it filter the suggestion, just Up/Down key.<br>
  I have try:</p>
  
  <pre><code>  completer-&gt;setModel(w-&gt;model());
  </code></pre>
  
  <p>but no help!<br>
  What is my misstake or just QStringListModel give me the ability to filter the suggestions? What do you suggest?<br>
  Thanks you!</p>