title: Window icon does not show
body: <p>I study this tutorial <a href="http://zetcode.com/gui/pyqt5/firstprograms/" rel="nofollow noreferrer">http://zetcode.com/gui/pyqt5/firstprograms/</a>
   and code here.</p>
  
  <pre><code>import sys
  from PyQt5.QtWidgets import QApplication, QWidget
  from PyQt5.QtGui import QIcon
  
  
  class Example(QWidget):
  
      def __init__(self):
          super().__init__()
  
          self.initUI()
  
  
      def initUI(self):
  
          self.setGeometry(300, 300, 300, 220)
          self.setWindowTitle('Icon')
          self.setWindowIcon(QIcon('web.png'))        
  
          self.show()
  
  
  if __name__ == '__main__':
  
      app = QApplication(sys.argv)
      ex = Example()
      sys.exit(app.exec_())  
  </code></pre>
  
  <p>Can I show Window icon? I use PyQt5, Python3.4 and Linuxmint 17.2 cinnamon.</p>
  
  <p><a href="https://i.stack.imgur.com/Vf0dL.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Vf0dL.png" alt="This Window"></a></p>