SYMPTOM:
A Database Instance cannot be deleted from the Configuration Managers -> Database Instance display because there are still dependent objects after un-checking the Database Instance in the Project Configuration Editor. When searching for dependents using the Search Editor none appear in Desktop.
CAUSE:
This is a known issue in Strategy. Even though no dependencies are listed, there are system objects that depend on the database instance.
ACTION:
Contact Strategy Technical Support for an update on the issue.