Paul,

A cbo set to Style - DropDown List will work exactly like that. It'll give them incremental search too, so all they have to do is type enough to be unique.

>Experienced users of the system know the codes and would like to directly enter the codes and then tab to the next textbox. I've set the tab order to so that the textboxes are at the top of the order with the combo boxes at the bottom.
>
>The users only want the combo boxes to display if they make a mistake in the textbox entry.