Security Alerts Very Slow to Clear when I Click Allow or Block

Help Please

I have run Comodo Firewall with No Problems until now.

When I try to connect to the web after the Firefox interface has been changed by a application,
the Security Alert Screen shows, then when I click Allow or Block , the Screen stays for several minutes before it allows internet connection.

Is this because the list of allowed applications is to big ?

If so how do I clear some of them ?