title: Correct use of the .clear() method on QDateTimeEdit
body: <p>The following script is creating a very simple GUI containing a QDateTimeEdit and a QPushButton only (the script can be run):</p>
  
  <pre><code>import sys
  import os
  from PyQt4 import QtGui
  from PyQt4 import *
  
  class SmallGUI(QtGui.QMainWindow):
      def __init__(self):
          super(SmallGUI,self).__init__()
          self.initUI()
  
      def initUI(self):
          self.setGeometry(300,300,300,300)
          self.setWindowTitle('Sample')
  
          #Calendar input
          self.MyInput = QtGui.QDateTimeEdit(self)
          self.MyInput.setCalendarPopup(True)
          self.MyInput.setDisplayFormat("dd/MM/yyyy hh:mm")
          self.MyInput.setGeometry(88,25,110,20)
          ###############
  
          #Clear button
          self.MyButton = QtGui.QPushButton(self)
          self.MyButton.setGeometry(QtCore.QRect(88,65,110,20))
          self.MyButton.setText('Clear date')
          ###############
  
          QtCore.QObject.connect(self.MyButton,QtCore.SIGNAL("clicked(bool)"),self.clearDate)
  
          self.show()
  
      def clearDate(self):
          self.MyInput.clear()
  
  def main():
      app = QtGui.QApplication(sys.argv)
      sampleForm = SmallGUI()
      sys.exit(app.exec_())
  
  if __name__ == '__main__':
      main()
  </code></pre>
  
  <p>When I click the "Clear date" button, however, the method .clear() of the QDateTimeEdit is clearing the first two values only (just the day) and it seems stopping at the "/". I have tried to read some documentations of the object but I couldn't find my way. Does anyone know how I can completely empty the input box when the button is pressed? </p>