Not sure what to say. I'll have to say, because of the new firefox forced changes on foxyproxy, it has now become unusable for me, even since the new version before FF 57 rolled out. I had to revert to the old version to make it work when I was still using FF 56 and earlier versions. Now with FF 57, there doesn't seem to be a way to revert to earlier versions, then the current foxyproxy no longer works, even though all the proxy and patterns look the same as before.

Downthemall and flashgot and a few other important add-ons also become invalid. I guess it is time for me to abandon Firefox for good finally, despite that I have been using it (and its predecessor) for the past 20 years.