WORKAROUND:
Go to View | Toad Options | Editor – Code Assist, un-check all objects that are not being used; i.e. Sequence, Public Synonyms, Procedures, Packages, etc. and only check objects that are intended to be selected from the Pick List (Tables, Views, *Users) and try again.
*Users should be checked, especially is the queries being used contains the schema name (i.e SELECT * FROM Schema1.table1)
Note:Public Synonyms are known to have performance issues (not related to code insight, this is is an Oracle issue), but gets even worse on a large DB like Oracle Apps.
STATUS:
This issue is fixed in Toad for Oracle 12.7. This version can be downloaded from the downloads section of our website, which you can access by clicking here.
