Userscript for disabling tab scroll

noTabScroll.uc.js

// ==UserScript==
// @name            noTabScroll
// @author          blackle
// @include         main
// @startup         UC.noTabScroll.exec(win);
// @shutdown        UC.noTabScroll.destroy();
// @onlyonce
// @shutdown
// ==/UserScript==

const {
  MozElements,
} = window;

UC.noTabScroll = {
  exec: function (win) {
    let {customElements} = win;

    customElements.get('arrowscrollbox').prototype.on_underflow = function (e) {
      e.preventDefault();
    };
    customElements.get('arrowscrollbox').prototype.on_overflow = function (e) {
      e.preventDefault();
    };
    customElements.get('tabbrowser-tabs').prototype._initializeArrowScrollbox = function () {
      return;
    };
  },

  destroy: function () {
    delete UC.noTabScroll;
  }
}