Review by GiNeR is right about "small issue" with button, but wrong about proxy state. Right after start of firefox this add-on shows green button but state of the proxy is "off" (wrong colour of the button and wrong subscript "Turn off proxy" with mouse pointer over button, I suppose). After first click on the button - proxy state goes to "system" and after subsequent clicks toggles between "system" and "manual" (as it should be without mismatch of button colour). So I think "small issue" would be resolved if 1) correct colour of the button would be set right after start of firefox 2) first click should change proxy state directly to "manual". Or may be optionally implement saving proxy state across firefox restarts as GiNeR wrote.

Anyway it is the simplest and fastest (one-click only management) add-on you could find.

I like that it uses builtin FF settings instead of its own like some other extensions, no need to overcomplicate things.

Wishlist:
* Customizable keyboard shortcut
* Different icon color for "off" state. Green and blue are too similar.

Works perfectly and I think I love it but unfortunately it requires private windows access "due to a Firefox update" and I am not sure I like it. So I give it 4 stars instead of 5 for the private access thing.

Very simple and just works by enabling disabling Firefox proxy settings. There is one small issue though, proxy switches on automatically when browser restarts even if it was disabled.

Ben: did you follow the directions in the add-on description

Me: Yes, I did try that, still it turns on (the button becomes green) after restart. I would expected it remember the last state and restore on restart.