Binding Navigator - how do you get Validate to fire when someone clicks the add button more than once?

I've been trying, once again, to do some of the simplest things with the BindingNavigator tied to a BindingSource and without generating errors.
One thing I can't seem to solve, it that if a user clicks the "Add" button on the BindingNavigator more than once, it attempts to save the previous record without firing the Validate event (and saves nulls even though they are trapped in the dataset partial class).
Clicking the Save icon, I can trap that click event and run a save routine and validation works just fine.
Since there seems to be no way to enforce validation rules (on the recordset) during this situation, I need to disable the add button after it is clicked once or somehow prevent the button from being active if the current record has not been saved or validated.
Code to follow - hopefully soon