Normally, data lookups in Dynamics 365 for Finance and Operations display a list of records where the first column always contains a value, which is returned to a calling form. The first column in the lookup normally contains a unique record identification value, which is used to build relations between tables. For example, the Customer lookup displays the customer account number, the customer name, and some other fields; the Inventory item lookup displays the item number, the item name, and other fields.
In some cases, the record identifier can be not so informative. For example, it is much more convenient to display a person's name versus its number. In the standard application, you can find a number of places where the contact person is displayed as a person's name, even though the actual table relation is based on...