After upgrading from to Toad for Oracle 220.127.116.11, the Toad Insight box does not appear for table aliases in the Editor. Instead, it shows all the objects starting with the alias letters.
Use Toad for Oracle 9.5
Waiting for fix in a future release of Toad for Oracle
This is specific to version 18.104.22.168. It works correctly in version 9.5.