title: PyQt4 menubar doesn't appear in Ubuntu
body: <p>I am using python with Pyqt4 for building app on Ubuntu and seems I have trouble with menubar that doesn't show up, thanks for any help. here is the code:</p>
  
  <pre><code>import sys
  from PyQt4 import QtGui
  class Example(QtGui.QMainWindow):              
      def __init__(self):
           super(Example, self).__init__()        
           self.initUI()        
      def initUI(self):                      
           exitAction = QtGui.QAction(QtGui.QIcon('exit.png'), '&amp;Exit', self)        
           exitAction.setShortcut('Ctrl+Q')
           exitAction.setStatusTip('Exit application')
           exitAction.triggered.connect(QtGui.qApp.quit)
           self.statusBar()
           menubar = self.menuBar()
           fileMenu = menubar.addMenu('&amp;File')
           fileMenu.addAction(exitAction)        
           self.setGeometry(300, 300, 300, 200)
           self.setWindowTitle('Menubar')    
           self.show()       
  def main():    
      app = QtGui.QApplication(sys.argv)
      ex = Example()
      sys.exit(app.exec_())
  if __name__ == '__main__':
       main()  
  </code></pre>
  
  <p>Excuse me if the indentation wouldn't be correct but I think it is.</p>