Well, we figured it all out.

The first record with the ldefault field in the metaDBC set to true becomes the default database used by builders, prefereneces etc.

The prefereneces form (with the cDataMgrMetaData set to true) has a combo box into the metaDBC table that lets you select any of the records (databases) to edit the data path. If you select OK, the changes are written back to the metadbc table for that record. The database key (dimmed) on the form is not related to changs in the combo box. It is just there to show which record it has selected as the default.

Gary.