WebRunner doesn't work in java embedding

Hi,

I'm having some trouble to run a XUL application like WebRunner (http://wiki.mozilla.org/WebRunner) in XULRunner embedded in Java.  Following the example given by http://developer.mozilla.org/en/docs/JavaXPCOM:Embedding_Mozilla_in_a_Java_Application_using_JavaXPCOM I can run any simple XUL application just fine.  However when I tried to run WebRunner, the javascript calls to xpcom doesn't seem to work.

The WebRunner app has a xul file like this:

<?xml version="1.0"?>
<?xml-stylesheet href="chrome://global/skin/" type="text/css"?>

<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
        id="webrunner"
        windowtype="webrunner:main"
        title="WebRunner"
        width="750" height="550"
        screenX="10" screenY="10"
        persist="width,height,screenX,screenY">

  <script type="text/javascript" src="chrome://global/content/globalOverlay.js"/>
  <script type="text/javascript" src="webrunner.js"/>

  <popupset>
    <popup id="main-popup">
      <menuitem id="cut-menuitem" label="Cut" oncommand="goDoCommand('cmd_cut');"/>
      <menuitem id="copy-menuitem" label="Copy" oncommand="goDoCommand('cmd_copy');"/>
      <menuitem id="paste-menuitem" label="Paste" oncommand="goDoCommand('cmd_paste');"/>
      <menuitem id="delete-menuitem" label="Delete" oncommand="goDoCommand('cmd_delete');"/>
      <menuitem id="selectall-menuitem" label="Select All" oncommand="goDoCommand('cmd_selectAll');"/>
    </popup>
  </popupset>

  <browser id="main-browser" flex="1" type="content-primary" context="main-popup"/>

  <statusbar>
    <statusbarpanel id="status" label="" crop="end" flex="1"/>
    <progressmeter id="progress" mode="determined" value="0%" style="display: none"/>
    <statusbarpanel id="security" label="" style="display: none"/>
  </statusbar>

</window>

When embedded in Java, the main window titled "WebRunner" with statusbar pops up just fine, but the javascript (webrunner.js) calls to xpcom objects don't seem to work.  Here's the javascript part that matters:

const nsIWebProgress = Components.interfaces.nsIWebProgress;
const nsIWebProgressListener = Components.interfaces.nsIWebProgressListener;

window.addEventListener("load", startup, false);
window.addEventListener("unload", shutdown, false);

function startup()
{
  // hookup the browser window callbacks
  window.QueryInterface(Components.interfaces.nsIInterfaceRequestor)
        .getInterface(Components.interfaces.nsIWebNavigation)
        .QueryInterface(Components.interfaces.nsIDocShellTreeItem)
        .treeOwner
        .QueryInterface(Components.interfaces.nsIInterfaceRequestor)
        .getInterface(Components.interfaces.nsIXULWindow)
        .XULBrowserWindow = gXULBrowserWindow;

  // hookup global webprogress listener
  var dls = Components.classes["@mozilla.org/docloaderservice;1"].
                       getService(Components.interfaces.nsIWebProgress);
  dls.addProgressListener(browserProgressListener, nsIWebProgress.NOTIFY_ALL);


  var browserContext = document.getElementById("main-popup");
  browserContext.addEventListener("popupshowing", popupShowing, false);

  var cl = window.arguments[0].QueryInterface(Components.interfaces.nsICommandLine);
  var startURI = cl.handleFlagWithParam("uri", false);
  if (startURI == null) {
    startURI = "http://mozilla.org"
  }

  var browser = document.getElementById("main-browser");
  browser.webNavigation.loadURI(startURI, 0, null, null, null);
}

function shutdown()
{
  window.removeEventListener("load", startup, false);
  window.removeEventListener("unload", shutdown, false);

  var browserContext = document.getElementById("main-popup");
  browserContext.removeEventListener("popupshowing", popupShowing, false);
}

What should happen is that the browser in the main window goes to url http://mozilla.org on load.  Instead, nothing happens.  At first I thought somehow the startup() function didn't run.  But that's not the case.  If I add something like 'alert("Hello");" to startup() it works just fine.  That gives me the impression that when being embedded in java, somehow all the xpcom calls from javascript are silently failing.

Please advise whether this should work, and if so how to fix it.

Thanks in advance for your help!

J.J. Zhuang