Undoing macro actions

[David]

I have a check box field in a datasheet form which, ON
CLICK, inserts some text (via the SETVALUE action) into
its respective record.

I would like to be able to unclick the check box and
allow the text which I had previously to reappear. Is
this possible?

Unfortunately, the UNDO button seems to be limited to
undoing text changes to the record being updated and none
prior.

Thanks in advance.