Parameter request with linked combos

[barrysprout]

I have a combo box on a form whose results are filtered by a parameter that is supplied by the value in another combo box like so:

Combo1 = country
Combo2 = customers of country entered in combo1

This works fine but when I close the form using a menu or button (and not the form's default close tool, strangely enough), I get a parameter request for the country. This seems to be coming from combo2 because if I delete the combo, the parameter is no longer requested. I can’t seem to get rid of this bug. Any ideas?