title: QFont::setPointSize: Point size <= 0 (-1), must be greater than 0
body: <p>I did a mainwindow.ui file converted into Ui_mainwindow.py (pyuic4). 
  Next I used the class from this .py file like this:</p>
  
  <pre><code>class MainWindow(QMainWindow, Ui_MainWindow):
      def __init__(self, parent = None):
          super(MainWindow,self).__init__(parent)
          self.setupUi(self)
  if __name__ == "__main__":
      app = QtGui.QApplication(sys.argv)
      myapp = MainWindow()
      myapp.show()
      sys.exit(app.exec_())
  </code></pre>
  
  <p>When I run the code in ipython, the following message appeared:
  QFont::setPointSize: Point size &lt;= 0 (-1), must be greater than 0</p>
  
  <p>Here the .ui link:
  <a href="http://txtup.net/DDvZH" rel="nofollow noreferrer">mainwindow.ui</a>
  Here the .py from .ui link:
  <a href="http://textuploader.com/?p=6&amp;id=GFCG" rel="nofollow noreferrer">Ui_mainwindow.py</a></p>
  
  <p>ipython terminal remain in bug state even if the app works.
  When I quit app (No error or warnings), ipython is still in this state.</p>
  
  <p>Here the link picture bug:<a href="https://i.imgur.com/OYhNBRI.png" rel="nofollow noreferrer">ipython bug</a>
  <img src="https://i.stack.imgur.com/TKiFF.png" alt="ipython bug"></p>
  
  <p>Could someone explain me how to avoid it?</p>