Firefox extension icon in navigation bar using Add-on-builder

Question

How to add an icon in Firefox that opens a panel when you click on a navigation bar. An example is the Firebug extension. The only thing that will be different is that I want the panel to appear.

Thanks!

Answer 1

You might want to use or view this toolbar library:

https://builder.addons.mozilla.org/library/1006210/latest/