How do I get the "Twitter App" icon back in the Firefox toolbar?

Question

Mozilla Firefox

After updating the 'Firefox' browser to version 44.0, the Twitter extension "Twitter App" disappeared from
the toolbar. In browser extensions, it ("Twitter App") is present, but it is not on the browser panel.
Twitter App turned off and on, but it never appeared on the browser panel.
What needs to be done to bring it back? Roll back to the previous version of the browser ?, it was some kind of sewing.

Answer 1

1. How to customize toolbars, controls...
2. Also, the add-on can be disabled due to not having the add-on's signature.
about:config
xpinstall.signatures.required = false

Answer 2

Decided to stupidly score and not bathe. I'll go drink vodka better.