>In this case, however, the user cannot add or edit the feild - so I thought the combo would be a better UI for the purpose....

But a large list of items is hard for a user to navigate in a list (grids are much nicer) and they may break down (aka: Not Work) with a lot of records. You might want to try combining a Grid and a Textbox the way the standard combo combines a listbox and a textbox, try past FoxTalk articles for more information.