Block Browser in Proxy not working?

[PotatoCarl]

Hi

I try to block certain browser (IEx <11, older Windows Versions) from access the internet. A field in the proxy configuration offers to do so. But it does not have any effect. Even when I block everything (^Mozilla) I can continue to browse.

Check the squid.conf file at /usr/local/etc/squid/squid.conf shows that there are in fact no entries for browser, NOR the strings I entered in the web interface are anywhere to be found.
I believe this must be some kind of bug.

Or I am too stupid to enter ^(.)+MSIE\.9 ? ^(.)+Windows\XP not working either...