Rated 5 out of 5 stars

For those who didn't notice, last FF update (18) broke the addon (not the other way around). Just tried using FF 19 beta and addon works well with it, so just use the beta or wait for a stable new release :)
(and removing http and https doesn't solve the issue as we don't get a 400 error, but the custom headers are ignored anyway) Awesome addon btw (installed on my FF since first release)