I am a new user of Toad Data Modeler. The beta is impressive and I really appreciate the Postgres support.
My issue is with the Serial Datatype. When I create an identifying relationship to another table the FK attribute automatically gets created as a Serial and can not be changed. I believe it should be created as an integer. According to the PostgreSQL documentation a serial is of type integer.
What I did for now is create a sequence and the PK attribute as an integer. This creates a FK attribute of the same type and all is well.