title: QGraphicsItem unselect redraw problem
body: <p>Very simple Qt GUI application: </p>
  
  <ul>
  <li>On the scene I have multiple circles implemented as QGraphicsItem</li>
  <li>boundingRect returns square around
  this circle.</li>
  <li>Method 'shape' is not overridden.</li>
  </ul>
  
  <p>The problem appears when in paint() method I've added:</p>
  
  <pre><code>if (isSelected()) {
      painter-&gt;drawRect(re);
  }
  </code></pre>
  
  <p>Selection is drawn well, but unselection doesn't cause redrawing. At log level I can see that item really lost selection flag. 
  Calling update() from itemChange is useless also. 
  Thank you in advance for any suggestion.</p>