Today, it is not possible to use a lookup on Option or Enum fields with a table relation on a table consisting of an Enum or Option field as primary key. The lookup would be just empty.

Use case: Sometimes Enums can consist of a large list of values. By providing an intermediate table, users could select which of these enum values they actually need and therefore should appear in lookups or drop-downs.

For more details and sample code, see https://github.com/microsoft/AL/issues/6335.