Combobox not respecting the "Show As" setting...
Not sure if there are tweaks to correct this, but it does throw off the grace of the UI.
If you are using a Combobox with a Reference field linked to another table try the following:
1. Do not use the Show As setting.
2. Start with the Reference link as a Popup.
3. Click the Wrench to enter Admin mode. (Important to be in admin mode)
4. Unlink the link in the Reference field if recond is already linked.
5. Click the Reference field to bring the Popup window into view.
6. Hide the columns not desired in the Combobox.
7. Sort the field as you want the Combobox to show the data.
8. Then select the record that you want to link as you normally would in the Popup window.
9. Once you are back at the recond, save the changes. (Important)
10. Now enter the Reference field configuration dialog and change the Popup to a Combobox.
11. I did not use the Show As field.
12. Use the Constraints field if you want to filter the Combobox, such as showing only active employees but not terminated employees.
13. Save the changes and return to the table's data view.
14. Tip: You may need to leave the table (select another table, then return to the table) to cause the Constraint field to start working.
15. Now try the Combobox. It should show the picklist of data desired.
No promises but it works for me very well.