How to block accessing Loopback??

Hi guys.I have a problem with CFW.I know that there is an option to enable alerts for loopback and I’ve already enabled it.But still programs can connect to internet through loopback.For example when I block Firefox and define it as a Blocked Application,When I set it to use Proxy through at port 8080 and I run a Proxy software that handles traffic from ,it can connect to internet.I’m using CFW and Avast 7 Free (Disabled Webshield).???

What configuration are you running? Can you check under More → Manage My Configurations?

My configuration is Imported from previous version.

here is a 17 page discussion about the issue with Avast7 and loopback filtering.
Short version, Avast7 uses some feature that causes 3rd party Firewall’s to leak, Comodo is working on a fix but I expect that it will be no earlier then version CIS 6.
Or you can chose to run Avast 6 instead of 7.