private void ProcessNotes(CellClass cell, Int32 index)
        {
            switch (cell.CellState)                                     // What is the cell state?
            {
            case CellStateEnum.Notes:                                   // Already showing notes?
                cell.Notes[index].State = !cell.Notes[index].State;     // Yes, then toggle the state of the specified note
                break;

            case CellStateEnum.Blank:                                   // Blank?
                cell.ClearNotes();                                      // Clear all notes
                cell.CellState          = CellStateEnum.Notes;          // Set the state to notes
                cell.Notes[index].State = !cell.Notes[index].State;     // Toggle the state of the specified note
                break;
            }
        }