David,

In this case dump the rowsource you are using and use a rowsourcetype of Fields, then set the columncount to the number of fields you want to display in the combo. Then set thr rwosource to alias.field1,field2,... use the same alias as the rest of the form. Now using the combo will move the record pinter in the alias so all you need is to refresh the form from the interactivechange or the valid.

By the way, I am a firm believer that it should be impossible for a user to make an invalid selection in a combo. You ahve complete control over what is in the list and therefore should remove any items that are invalid.