Cascaded Combos in an Unbound SubForm - Parent Form Validation Failure

[DaveTheRave.NET]

I have created a borderless form that I can reuse in my Access
Application. It contains a number of cascaded combo boxes with each
subsequent combo's rowsource being set by a selection from the one
above.
The VBA coding allows the combos to select a foreign key when the last
combo value is selected. This foreign key is passed out as an event.

The problem I'm having is that, if I enter a primary key value into
the parent form, any attempt to access a Combo in the subform causes a
validation of the parent form's data. Since most fields require a
value, this fails.

Does anyone know how I can sort this out? Is there any way of making
the subform appear as if it is part of the parent form or suspending
the validation?

Thanks,
David Rocke.