About user-defined data types
You can create user-defined data types and add values to them using the User Defined Types form. Value and Description pairs display in a two-column list for each type that you define. The list of all values for all user-defined data types are included in the User Defined Type Values form.
After a user-defined data type is specified as the source for a component that supports lists (a combo box, for example), users can add values to the type directly through the right-click menu function. In the example provided, a user might add the value "X-Large."
User-defined data types are often useful with user-extended tables (UETs). They can also be used with user-defined fields. Users can add list-type components to forms without modifying the schema or IDOs or writing special form code.