title: QGraphicsItem paint not called
body: <p>I use <code>QGraphicsView</code>, <code>QGrapichsScene</code> and <code>QGraphicsItem</code> for drawing some charts. I have implemented <code>QGraphicsItem::paint</code> function for drawing text (values of charts), but it is not being called every time that is must draw something new. My <code>paint</code> function</p>
  
  <pre><code>    void CLabelItem::paint(QPainter *painter, 
  const QStyleOptionGraphicsItem* /*option*/, QWidget* /*widget = 0*/)
  {
  
      if ( GetValue() &lt; 0 )
      {
          return;
      }
      painter-&gt;drawText(boundingRect(), m_value.toString());
  }
  </code></pre>
  
  <p>So my question is - why <code>QGraphicsItem::paint</code> can be not called and how may I make it to be called?</p>