title: PyQt, Qtable clears column when sorting enabled
body: <p>I have a bug in next function. This function refreshes table with, adjust column sizes and sorts table. But in some cases for some rows text in column 3 and 4 is empty. I found out, that it happens in "problem code" section.
  What do i wrong in this section? I just want to change size for specific columns. 
  Please help to find out the problem or show me my mistakes.</p>
  
  <pre><code>def print_day_worklog(self):
      logging.info('RefReshing day worklog table')
      selected_day = self.ui.dateDayWorklogEdit.date().toPyDate()
      day_work = db.get_day_worklog(self.creds[3], selected_day)
      self.ui.tableDayWorklog.setRowCount(len(day_work))
      for row, entry in enumerate(day_work):
          e0 = QtGui.QTableWidgetItem(entry[0])
          e1 = QtGui.QTableWidgetItem(entry[1])
          e2 = QtGui.QTableWidgetItem(entry[2].strftime('%H:%M'))
          e3 = QtGui.QTableWidgetItem(entry[3].strftime('%H:%M'))
          e4 = QtGui.QTableWidgetItem(utils.get_time_spent_string(entry[2],
              entry[3]))
          # debug
          print e0.text(), e1.text(), e2.text(), e3.text(), e4.text()
          self.ui.tableDayWorklog.setItem(row, 0, e0)
          self.ui.tableDayWorklog.setItem(row, 1, e1)
          self.ui.tableDayWorklog.setItem(row, 2, e2)
          self.ui.tableDayWorklog.setItem(row, 3, e3)
          self.ui.tableDayWorklog.setItem(row, 4, e4)
  
      # problem code starts
      self.ui.tableDayWorklog.horizontalHeader().setResizeMode(1,
          QtGui.QHeaderView.Stretch)
      for column in (0,2,3,4):
          self.ui.tableDayWorklog.resizeColumnToContents(column)
          self.ui.tableDayWorklog.horizontalHeader().setResizeMode(column,
              QtGui.QHeaderView.Fixed)
          self.ui.tableDayWorklog.horizontalHeader().setResizeMode(column,
              QtGui.QHeaderView.Fixed)
      self.ui.tableDayWorklog.sortByColumn(2,0)
      # problem code ends
  </code></pre>
  
  <p>P.s. it looks not clearly, but it's because i try to catch the bug</p>