title: Segmentation fault in QGraphicsView::setScene()
body: <p>I have a normal widget application which should show a finite automata in a graphic view widget. I add a QGgraphicsView to the main window, which has an instance of QGraphicsScene:</p>
  
  <pre><code>MainWindow::MainWindow(QWidget *parent) :
      QMainWindow(parent),
      scene(new QGraphicsScene(this))
  {
      setupUi(this);
      scene-&gt;addText("Hello");
      ui-&gt;graphicsView-&gt;setScene(scene); // bumb!
  }
  </code></pre>
  
  <p>Program crashes by a segmentation fault when it tries to set scene for graphicsView.</p>