scroll problems

[Admini]

I think I found it, I have a script in tampermonkey to disable all these annoying "close this page" popups,
here's the code:

Code:

// ==UserScript==
// @name kill_beforeunload
// @namespace Violentmonkey Scripts
// @include     *
// @grant none
// @run-at document-start
// ==/UserScript==
//

EventTarget.prototype.addEventListenerBase = EventTarget.prototype.addEventListener;
EventTarget.prototype.addEventListener = function(type, listener)
   {
     if(type=="beforeunload") {
         return; //ignore attempts to add a beforeunload event
     }
     this.addEventListenerBase(type, listener); //treat all other events normally
};

function unsetOnBeforeUnload() {

   window.onbeforeunload = function(event) {};

   setTimeout(unsetOnBeforeUnload, 300); //optional, but some pages might set the event later in the page's lifecycle

}

document.addEventListener("DOMContentLoaded", unsetOnBeforeUnload);

I disabled it for youtube and now scrolling works when I switch to new comments for example,
which was impossible to work without that

I think there is dead loop in this script.