Never drag out a new tab.
// ==UserScript==
// @name Firefox Newtab Disabler for GitHub Projects
// @namespace http://github.com/DuckSoft
// @version 0.1
// @description Never drag out a new tab.
// @author DuckSoft
// @match *://github.com/*/projects/*
// @grant none
// ==/UserScript==
(function() {
'use strict';
document.body.ondrop = e => {
e.preventDefault();
e.stopPropagation();
}
})();