If you are thinking going that way, I would suggest that the password history is tied to the windows user. (If it isn't already, don't know as I don't save passwords)
I.e. if Marco logs into the machine after me, he can only see his history.
That way you don't have to remember/type in yet another password for PL/SQL developer, and all your history is safe. Of course, this assumes that you keep your PC locked when you are away.