Change behaviour of ENTER in selection with VBA

@karedog:
I don't follow the logic of the following lines, first private sub:

If CrossRange Is Nothing Then
     Application.EnableEvents = False
       Application.Undo
         Set CornerCell = ActiveCell
       Application.Undo
     Application.EnableEvents = True
     CornerCell.Offset(1).Activate

The code works fine without it, what am I missing?

Regards,
Henk