code: def paintEvent(self, event):
          
          super(AutoParameterTableView, self).paintEvent(event)
  
          if self.dragline is not None:
              pen = QtGui.QPen(QtCore.Qt.blue)
              painter = QtGui.QPainter(self.viewport())
              painter.setPen(pen)
              painter.drawLine(self.dragline)
docs: Adds cursor line for view if drag active. Passes event to superclass
          see :qtdoc:`qtdocs<qabstractscrollarea.paintEvent>`