Dynamic Constraints Language validation

Section 6.2.7 of the WD discusses how validation using Dynamic Constraints
Language will be triggered. Specifically it says "the specified Dynamic
Constraint is invoked every time the value of the declaring datatype
changes". Maybe I'm mistaken (and certainly "declaring datatype" goes
largely undefined), but I interpret this to mean that DCL validation will
occur only when the instance value of a model item changes. I think this
ignores the reality that the Dynamic Constraints themselves will change over
time. I believe there has to be an "always validate" mechanism to cause
validation to occur any time a model item has "lost focus", regardless of
whether the instance value changed. This enables new DCL validation to be
applied to existing data (where the WD more simply allows existing
validation to be applied to new data). For this reason, I also believe the
"always validate" mechanism should be an "XForms specific property"
applicable to any datatype.

Thanks,
John Liston