Review for Gmail Manager NG by Schtritoff
Rated 5 out of 5 stars
I've also had problems in the last few days with multiple google apps accounts. What help in my case was to write ABOUT:CONFIG in address bar, find "longfocus" entrys and deleted there written values (blanked them; there was leftovers from previous extension like old version number, etc). After that, I reinstalled latest version from github link and it worked.
Thanks to the new maintainer!
To create your own collections, you must have a Mozilla Add-ons account.