code: def onMouseOver(self, event, grid):
          
          x, y = grid.CalcUnscrolledPosition(event.GetX(), event.GetY())
          coords = grid.XYToCell(x, y)
          col = coords[1]
          row = coords[0]
  
          # creates tooltip message for cells with long values
          # note: this works with EPD for windows, and modern wxPython, but not with Canopy Python
          msg = grid.GetCellValue(row, col)
          if len(msg) > 15:
              event.GetEventObject().SetToolTipString(msg)
          else:
              event.GetEventObject().SetToolTipString('')
docs: Displays a tooltip over any cell in a certain column