'REQUEST' exists, then variable 'cell' becomes request value and
breaks matrixbox. I must check what must be done when cell is None.
when cell is explicitly specified as None, is it ok to override,
I do not have answer yet.


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@45397 20353a03-c40f-0410-a6d1-a30d3c3de9de