Did you inspect the SQL being executed when you requested the user to be 'dropped' in SQL Developer?
I'm guessing what you're seeing is recursive SQL being executed by the database in response to your 'simple' DROP USER command issued by SQL Developer. So not really a 'SQL Developer' specific question.
Thank you. That was it. I really didn't think about it being recursive SQL being executed by Oracle. I see this occurring in a DBCA-created database that has all of the Oracle products installed in it. This doesn't occur in databases that don't have all of the products installed. Thanks for the reply.