Parse color and stroke width of tspan object correctly. Color and stroke width may inherited from parent node, a text. We can not use loadSVG._set_paint() that only parse current node. loadSVG._set_paint_style() are used to used inherited style by passing an aggreagated style.

function start_madbuilder() {
    var url = "chrome://MadBuilder/content/madbuilder.html";
    var browser = document.getElementById("content");

    browser.loadURI(url, null, null, true);
}