[Zope] - Forcing re-authentication

I'm having some problems in my ZPublisher application concerning authentication. In short it compiles to the following: - When a user connects to the application, an authentication is forced and the user logs in. - After a while, if the user wants to re-authenticate (in order to use a different userid), he/she has to close the browser in order to get a new login window. This is considered painfull. Is there a way to force re-authentication without leaving the browser (Mozilla)? Thx in advance. -- Pieter J. Kersten; Erasmus Universiteit Rotterdam, dept. DI&A/S&N, WH2-20, B. Oudlaan 50, 3062 PA Rotterdam, Netherlands; Voice: +31-10-4082599; Fax: +31-10-4527236