File Validation and LookUp 
File Validation and Lookup Sometimes a data field on a form requires file validation, that is, only valid entries are allowed. In this case, the data entered into a field is validated against a file containing the allowable entries. If an entry is not in the validation file, or no entry is made, a look up table is displayed showing the valid entries. You can then select an entry by using the mouse, or cursor movement keys (See Frequently Used Keys) to position the pointer bar over the desired entry and then pressing the Select button or "double-click" the left mouse button.