Hard to beat 1Password, period.

The add-on would not unlock, it would do nothing, and normally previous versions 1Password add-ons work right away, after signing into the account. So I did try to remove, and install again. I did try to quit Firefox, and launch again with same results. At the end, after submitting to tech support, I re-started the pc, and 1Password toolbar started working flawlessly as ever. Tech support sent me a message with instruction, and follow up. This shows commitment, and response time was quick. I didn't need to follow their suggestions, since my problem was solved.

So, if you bump into same issue, remember to restart your desktop, we used to do that all the time before.
And you can always reach tech support for clarifications.