Rated 5 out of 5 stars

IT WORKS AGAIN, YAY!
After reading thru many recent reviews, I took the hint & went to this link which, being an .xpi, automatically installed. Restarted Firefox, works great once again. Btw, my prob was the non-stop dialogue boxes requesting to login to each acct @ each Firefox launch--which they had already permission to do so. So I can't say for sure mine had to do w/Windows Updates (still, can't rule it out either). Missed this addon so much in its absence. THANX! I'll be re-donating after this.

https://github.com/downloads/athomas/mozilla-firefox-addons/gmail_manager-0.6.4.1.3-fx+sm.xpi