title: PyQt4 Checkbox not responding - OSX
body: <p>I am getting a really weird issue here. A simple python app with a checkbox 
  once I click on the checkbox (cb) it doesn't change its state and it doesn't change the GUI visualization. </p>
  
  <p>Any ideas ? </p>
  
  <p>Here is my python snippet </p>
  
  <pre><code>a = QApplication(sys.argv)
  w = QWidget()
  cb = QCheckBox("Auto-Launch", w)
  cb.move(220, 110)
  cb.stateChanged.connect(handleLaunch)
  </code></pre>