Rated 5 out of 5 stars
Works for Firefox Developer Edition (v55 x64) with e10s Multi-process enabled, unlike alternatives, but could use addition of Open Profile Folder, if possible, as extensions providing that don't work with e10s.This review is for a previous version of the add-on (188.8.131.52).
Thank you for your feedback, I knew that it works with multi-process enabled but I didn't test it with last versions.
As you probably know, with Firefox 57 all XUL/XPCOM based extensions will stop to work forever (sigh!!!!!), so for me the last official compatibility is with Firefox 52.
Of course in this situation it's impossibile to add new features for Firefox, I just hope that Thunderbird will keep XPCOM/XUL support long yet.