Just what i needed. Thanks to this add-on i could uninstall Firefox Stable and stay only with Firefox Developer Edition, with the same functionalities of multiple accounts, only 1 web browser and until now, at least, no problems to report. Maybe the system to have to use middle button click to open a tab with the profile of the tab that you actually are, is a little "annoying", but really, i would love that Firefox Stable has this add-on built-in, like Firefox Nightly has.