When a connection is closed that shouldn't save the password, TOAD keeps the password in memory until it is shutdown completely. So the connection can be re-established without needing to specify the password. How should TOAD ask for the password when reconnecting without shutting down?
1) Go to View | Options | Oracle | General and select the Passwords tab. Please disable both options.
2) Also ensure that the Save Passwords option in New Connection window is disabled.
3) Close Toad and start it again.
For future connections it will always ask for passwords.