<?xml version="1.0" encoding="UTF-8"?>
<window
    title="window.title.desktop;"
    orient="horizontal"
    xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
    xmlns:html="http://www.w3.org/1999/xhtml"
    onload="
    try
    {
        window.resizeTo(900,650);

        enableDesignMode = function()
        {
            var myframe = document.getElementById('theframe');
            myframe.contentWindow.document.designMode='on';
        }

    }catch(e){alert(e)}
    ">
    <vbox flex="1">
        <iframe id="theframe" src="http://www.google.com" flex="10"/>

        <textbox value="blah blah" />

        <button oncommand="enableDesignMode();" label="turn design mode on" />
    </vbox>
</window>