Tooltip message when hovering on cell with mouse in wx.grid wxpython

I have a wx.grid table, I want to set a tooltip when I hover on a cell, I tried Mike Driscoll's recommendation below, it works, but I can't select multiple cells with mouse drag anymore, it allows me to select only 1 cell max, please help:

self.grid_area.GetGridWindow().Bind(wx.EVT_MOTION, self.onMouseOver)

    def onMouseOver(self, event):
        '''
        Method to calculate where the mouse is pointing and
        then set the tooltip dynamically.
        '''

        # Use CalcUnscrolledPosition() to get the mouse position
        # within the
        # entire grid including what's offscreen
        x, y = self.grid_area.CalcUnscrolledPosition(event.GetX(),event.GetY())

        coords = self.grid_area.XYToCell(x, y)
        # you only need these if you need the value in the cell
        row = coords[0]
        col = coords[1]
        if self.grid_area.GetCellValue(row, col):
            if self.grid_area.GetCellValue(row, col) == "ABC":
                event.GetEventObject().SetToolTipString("Code is abc")
            elif self.grid_area.GetCellValue(row, col) == "XYZ":
                event.GetEventObject().SetToolTipString("code is xyz")
            else:
                event.GetEventObject().SetToolTipString("Unknown code")