Since a few nightlies, ActionButton from my addon no longer appear. The add-on code https://github.com/hfiguiere/tweet-that/blob/master/lib/main.js#L4 The add-on from AMO https://addons.mozilla.org/en-US/firefox/addon/tweet-that/?src=ss
Add-on uses the Add-on SDK.
Just to be clear: the add-on wasn't changed.
You need to repackage the add-on with the latest JPM. https://blog.mozilla.org/addons/2015/10/14/breaking-changes-let-const-firefox-nightly-44/
That's really unfortunate.