This is a fix for mantis 766 ( http://mantis.tokeek.de/view.php?id=766 )
Since the upgrade to Digest authentication, access to protected search
features was indeed disabled once the Digest nonce timed out.
After Digest auth timeout the browser no more sent authentication
information and as the search results page is not private, protected
features were simply be hidden without asking browser again for
authentication.
Adding a supplementary parameter when accessing the search results as
authenticated fixes this.