I don't know what's going on, exactly -- and I'm kind-of annoyed that your buttons don't show up in "Customize" ... but I'm using the new TabCenter extension from the Firefox Test Pilot and the result is that the only button that shows up in the diigo toolbar is the "Go premium!" button.
I've been a diigo user for years, although I have mostly used it to PUSH out content, and haven't socialized here a lot ... but every once in a while I want to post a public sticky on a page and find that I can't (the help says I only need 2 friends for that, but if that's still the case, then my account is stuck in 2006).
https://github.com/bwinton/TabCenter
https://testpilot.firefox.com/experiments/tab-center