Old topic that got bumped, but okay.
I tried this, it's very handy. Thanks snlildude.

I guess that could help already, but you shouldn't really need to do it, because it already automatically comes up with a list of close url's as you type them. All you have to do is get kind of close to it, then hit down until you get to the one you were looking for. I thought they had that the whole time, and it works just as good as an auto-complete thing.

This is very nice feature I have found out that over years there are so many more fetures in the firefox itself then it is showing. Probably because they this that these features are not good but maybe they are just further testing them. One way or the other I would like to see some better interface for editing all those options. Probably I will find some gadget in their extension repository.