I am a long-term fan of main Mozilla products -- Firefox and Thunderbird. I was using those for years under Linux (even weird Debian variants of Icedove and Iceweasel). After migrating to Mac OSX world I continued using them till today. Few days ago I have some serious system-issues and needed to make a clean/fresh install of El Capitan. Instead of just shuffling back all my old apps, I did some fresh installs of those too (not all thou). Anyways, I made a fresh install of FF and TB. With the latter I have one issue that I cannot figure out: in my old version I had installed some addon which allowed me separate tab for Google Hangouts (in Thunderbird, not Firefox). That I really loved, since then all my communications were under one app. Now, I cannot find that addon anywhere. What's that? Can anyone help me by pointing to the right place -- what was that thing I had in my old version of TB?? I cannot recall. [ Perhaps I should ask a question to the group that deals with early Alzheimer? :-P ]

Thanks PM