The Select Field window is used to select a field you want used in an expression. All fields from the file you are working with are available. Additionally, the fields from any lookup file are also available.

Current Selection The field shown in the Current Selection reflects the highlighted field in the list of fields.
List The list includes all fields in the file you are working with. The Name, Field Type, and Description are shown for each field.

The Lookup button is available for fields used to refer to a record in another file. This allows you to select a field from the lookup window. For example, let's say you are working in the Statement Manager and you want to see all clients who have a specific Category. The Category field is in the Client file, which is referenced by the Client ID. You would highlight the Client ID field and then click the Lookup button to display the fields in the Client file. You would then highlight the Category field that stores the Category number and click the Select button.

The Back button is available when the Lookup button has been used. The Back button is used to return from the list of fields in the lookup file to the list of fields in the original file you are working with.

The Select button will close the Select Field window and insert the field in the Current Selection into the expression being defined. Double-clicking a field in the list does the same thing.

The Cancel button will close the window without changing the expression being defined.