Love the extension.
1) Would it be possible to make a Thunderbird version?
2) An undo button would be great (when clicking on the pre-select configurations).
3) It took me a while to figure out what the lock and the eye symbol meant. I think it means that the lock is security related and the eye privacy related. Perhaps an tool-tip could be added when hovering over the icons.
4) Some of the settings could benefit from additional information when hovering over them.