If you click Show Related for a warehouse source instance object, the Show Related notebook displays any steps, subjects, or processes with first-level dependencies on that warehouse source instance. You can view second-level dependencies by clicking Show Related for each object with a first-level dependency.
Steps Populated
When you drop a warehouse source instance, steps that are populated by that warehouse source instance might produce unexpected results.
Subject Areas
Because subject areas only contains processes, dropping a warehouse source instance does not affect a subject area.
Processes
When you drop a warehouse source instance, processes that contain that warehouse source instance might produce unexpected results.