Question : Combobox values updated when selected versus typed

We ae baffled by something in a subform in access.  We have a combobox that a user selects a UPC for a Contracts Manufacturers Table.   There is are two adjoining tables.  I have put 2 text boxes to show you the IDs for this question.  Normally we wouldn't have those there.

If a user SELECTS a UPC, all works good.  Notice the first 2 boxes have the ID of 48 joining te tables.  If the user TYPES the UPC and presses tab or clicks elsewhere, it doesn't write the IDs to the joining tables.  Why?  Attached is the error when the user types.  The SELECT works perfectly.  

Answer : Combobox values updated when selected versus typed

on the property sheet of the combo, select the Event tab and see which property of the combo box is being utilized to populate the textboxes..

you may need the Afterupdate event to populate the textboxes