>Among the ways I can imagine are:
>fields' WHEN property: RETURN IIF(condexpr,.T.,.F.)
>intercepting a SAVE based upon the condexpr
>interactiveRowColChange: THIS.ReadOnly = IIF(condexpr,.T.,.F.)
>etc.

Might be the extra code you have;

WHEN code
RETURN CondExpr

Alternative
This.ReadOnly = CondExpr in the GotFocus