Don't show the icon in YouTube. I'm on Windows 10, Mozilla Firefox

Tried to use a script multiple times with no success. Installed, reinstalled, made sure javascript is enabled. Under EDIT I added each site. No luck..It is a script for Disqus that is supposed to make clicking on (show all replies) open all of them.

This is the script :
// ==UserScript==
// @name Disqus Expand Replies Firefox 0.4
// @version 0.4
// @description Expand all 'Show more replies' links when one clicked
// @author Nerf
// @match https://disqus.com/embed/comments/*
// @run-at document-start
// ==/UserScript==

window.addEventListener('mousedown', function(event) {
if (event.target.className.indexOf('show-children')>-1) {
var ar = document.querySelectorAll('a.show-children:not(.expanded)');
for (var a of ar) {
a.className += " expanded";
a.click();
}
return;
}
});

OK I tried with another script change app and it's probably nothing wrong with Greasemonkey just a script that doesn't work- but since it was the only reason I needed it I uninstalled both apps.

Completely breaks web page functionality (i.e. youtube) causing unpredictable behavior.

Manipuler Java c'est utile mais dans le même temps greasemonkey accède à une quantité de données personnelles illimitées et ça ce n'est pas acceptable.

The documentation is awful. It doesn't work and I don't understand why.

No longer works in waterfox classic. Will update this review accordingly if it starts working again.

Can't even get it to load. Firefox already installed I don't need 6 more additions.

I can not create a new user script. From popup menu "New user script..." not work!