you can set a proxy manually right... then toggle it on. check your IP and the proxy works. open the add-on back up (without toggling the proxy off btw) then go back and refresh your IP checker website... back to your regular IP. WITHOUT TURNING OFF THE PROXY TOGGLE. so if you toggle the proxy on, you can't go back into the add-on GUI unless you toggle the proxy off and back on again. this is really poorly coded and a huge security risk