title: Strange, double click/mouse dragging will trigger key event "CTRL-C"
body: <p>Qt seems to behavior strangely: when mouse double click or dragging on a widget, it will trigger the Ctrl-C key event. Here is my code:</p>
  
  <pre><code>class CWidget: public QWidget
  {
      Q_OBJECT
  
  public:
      CWidget()
      {
  
      };
      virtual ~CWidget()
      {
      }
  
  protected:
      void keyPressEvent ( QKeyEvent * event ) 
      {
          if (event-&gt;key() == Qt::Key_C &amp;&amp; (event-&gt;modifiers() &amp; Qt::ControlModifier))
          {
              qDebug() &lt;&lt; "strange copy: Ctrl-C";
          }
          QWidget::keyPressEvent(event);
      }
  }; // 
  </code></pre>
  
  <p>After the widget is shown, you can perform mouse double click and dragging around on it, and the debug message "strange copy:Ctrl-C" is printed. I have been searching over the internet for two days about this, and found nothing. </p>
  
  <p>Did I use it wrong or it is a bug of Qt?</p>
  
  <p>The code is tested under (vs2008 + Qt Addin + Qt 4.7.3) and (qcreator + Qt 4.7.3 ), xp sp2</p>