Why is the addon button not showing up?

Question

Programming

Good afternoon. I wrote an addon for myself, with the command "jpm run" it starts in a new clean Mozilla profile, the addon button is displayed, everything works. After that, I decided to put it on a daily profile - the button is not displayed anywhere, even the appearance setting is not there. I created a toolbar for this button - the situation is the same, in a clean profile everything is there - it is present in the list of toolbars, in the everyday one - there is not even a hint.
The button code is:

var buttons = require('sdk/ui/button/action');
var activated = false;
var button = buttons.ActionButton({
        id: "fast-copy-links",
        label: "Activate FCL",
        icon: {
                "16": "./deactivated-16.png",
                "32": "./deactivated-32.png",
                "64": "./deactivated-64.png"
        },
        onClick: toggleActivation
});

What's the matter - I can not understand, the entire Internet has already been rummaged. I don’t want to reset the profile, the only thing I haven’t tried to put on another browser. I don't know if this affects - I have the FF appearance customized for the old style, before the modern updates. But other plugins are installed without problems.

Answer 1

Disable all your extensions one by one and see what doesn't work. I checked it on a clean profile and basically, the latter has Classic Theme Restorer, but everything works both there and there.