Why can't I paste into youtube comments on firefox

I don't know when this happened, but today I noticed that I cannot paste text into Youtube comments on Firefox 40.0.3. It still works just fine on Chrome. I tried to use an addon to copy plain text only, but that didn't help, nor have I ever needed it before. Restarting the browser didn't help either.

What I mean is: When I press "paste" either by right clicking or Ctrl + V, nothing happens. I could still type into the comments normally. I can otherwise paste just fine to anywhere else, just not into Youtube comments...

Is this Google's latest monopoly trick or something, or what is going on?

Any ideas?

NOTE: The following "fix" has been known to cause problems on some sites. Please see this answer for a better solution.

Answered on Tomshardware by pcdude234:

I have a fix. go to your address bar and type "about:config" no quotes, and then hit the "i'll be careful, I promise" button, next type "dom.event.clipboardevents.enabled" then double click it, so the value is false. And that should do the trick.

Worked :P

This is a pretty old question now, but I re-installed windows a while back and when I ran into this problem again, I decided to find a better fix.

Don't touch about:config. This way, any other functionality dom.event.clipboardevents provides doesn't break.

Instead, install this userscript by Sergey Rozhenko. (Userscripts can be installed with the help of an addon such as Greasemonkey or Violentmonkey.)

// ==UserScript==
// @id             Fix paste on YouTube
// @name           Fix paste on YouTube
// @version        1.0
// @namespace      GrayFace
// @author         Sergey "GrayFace" Rozhenko
// @description    Fixes paste function in comments on YouTube
// @include        https://www.youtube.com/*
// @include        http://www.youtube.com/*
// ==/UserScript==

function handler(e){
    e.stopPropagation();
}

addEventListener('paste', handler, true);