How to make Toad for Oracle process queries in multiple threads.
In Toad 8.5 and 8.6:
1. Launch Toad for Oracle.
2. Connect to your database.
3. Go to View | Options | Oracle | Transactions.
4. On the right side, check the check box for "Execute queries in threads."
5. Restart Toad and establish a new connection.
In Toad 8.0, it can be found in View | Options | SQL Editor | View | "Process statements in threads / allow queries to be cancelled".