Generally , there is no need to set search path in editor and it should take by default from your user profile. In search path you define all schema names which the database will try to search for the function/table/schema etc if it does not found in search path schema, it will give you failure.
TDA only looks in current schema and 'public'
Type 'set search_path = ...' in the editor prior to running a query
Enhancement request ST86933 has been submitted to Development for consideration in a future release of Toad for Data Analysts.