I have two tables with a 1-1 relation (actually Super type- subtype), they have the same primary key.
I have a form bound to the super type, on this form I have a subform that is bound to the Subtype and is linked to the parent form via their primary keys.
My problem is that the subform allows entring two records on the subform. In other words, if you consider the Navigation buttons, after you enter the first record in the subform, it allows you to move to the second record, however if you enter it won't accept (Duplicated primary key)

My question is how can I disable moving to the next record?
(If I disable the navigation buttons it still moves to the next record when you tab off the last field on the subform)