Suddenly I guess I don't know how to design a form with a sub-form. The subform is a continuous form with a combobox. When a record is selected in the combobox, a field next to the combo box is auto-populated with this code:
Private Sub cboPartNumber_AfterUpdate()
Me.txtPartNdescription = Me.cboPartNumber.Column(2)
But then, and this is strange, the next record in the continuous form gets the field Me.txtPartNdescription populated with the same value as the first one.