title: does not show icons
body: <p>I just installed Python3 (3.5.2) and Pyqt5 (5.8.2) and I am following this tutorial to learn and make a GUI: <a href="http://zetcode.com/gui/pyqt5/firstprograms/" rel="nofollow noreferrer">http://zetcode.com/gui/pyqt5/firstprograms/</a></p>
  
  <p>I'm trying to run the 2nd example but program is returning an error (which also happened on the 1st one, but since it had no image i took no notice) which is the following:</p>
  
  <pre><code>QApplication: invalid style override passed, ignoring it.
  No XVisualInfo for format QSurfaceFormat(version 2.0, options QFlags&lt;QSurfaceFormat::FormatOption&gt;(), depthBufferSize -1, redBufferSize 1, greenBufferSize 1, blueBufferSize 1, alphaBufferSize -1, stencilBufferSize -1, samples -1, swapBehavior QSurfaceFormat::SwapBehavior(SingleBuffer), swapInterval 1, profile  QSurfaceFormat::OpenGLContextProfile(NoProfile))
  Falling back to using screens root_visual.
  </code></pre>
  
  <p>What is the meaning of this? Am i missing some packages?</p>
  
  <p>I installed pyqt first with this command:</p>
  
  <blockquote>
    <p>sudo -H pip3 install PyQt5</p>
  </blockquote>
  
  <p>but Python3 was not acknowledging its existence so i searched the apt ubuntu repos and installed with:</p>
  
  <blockquote>
    <p>sudo apt install python3-PyQt5</p>
  </blockquote>
  
  <p>I also tried to reference the image by full path /foo/bar/image.png and nothing</p>
  
  <p>What is the problem?</p>
  
  <p><strong>EDIT #1</strong></p>
  
  <p>The code that i am using is from example 2:</p>
  
  <pre><code>#!/usr/bin/python3
  # -*- coding: utf-8 -*-
  
  """
  ZetCode PyQt5 tutorial
  
  This example shows an icon
  in the titlebar of the window.
  
  author: Jan Bodnar
  website: zetcode.com
  last edited: January 2015
  """
  
  import sys
  import os
  from PyQt5.QtWidgets import QApplication, QWidget
  from PyQt5.QtGui import QIcon
  
  base_dir = os.path.dirname(os.path.abspath(__file__))
  os.chdir(base_dir)
  
  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('image.png'))
  
          self.show()
  
  
  if __name__ == '__main__':
  
      app = QApplication(sys.argv)
      ex = Example()
      sys.exit(app.exec_())
  </code></pre>
  
  <p>After your post i reinstalled all my packages. The error is slightly different but the result is the same:</p>
  
  <pre><code>python3 example_02.py 
  QApplication: invalid style override passed, ignoring it.
  </code></pre>
  
  <p>Screencapture:<a href="https://i.stack.imgur.com/Joxbx.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Joxbx.png" alt="Screenshot of my result"></a></p>