How to make links that open new windows work in XULRunner-based browser?

Using XULRunner, I’m working on a custom, kiosk-style browser for my
company. When clicking on a link that opens in a new window
(target=”_blank”), nothing happens. The JS console shows “No chrome
package registered for chrome://navigator/content/navigator.xul .” From
an LXR search for “navigator.xul”, I guessed a pref named
“browser.chromeURL” might have something to do with this (though not
referenced by a toolkit/ file), so I added it, pointing to my XUL file.

Now this works, but it will always open a new window. I actually want
to prevent links from opening in new windows, so I implemented
nsIBrowserDOMWindow and set the window’s browserDOMWindow property on
startup. However, my code never gets called (aside from
QueryInterface). As far as I see, I have done everything similar to how
Firefox does it - what am I missing?

I’d appreciate any pointers.

Best regards,
Jens

// in startup function:

window.browserDOMWindow = new MyProductBrowserAccess();// further below, same JS file:

function MyProductBrowserAccess()

{

}

MyProductBrowserAccess.prototype =

{

    QueryInterface: function ( iid )

    {

        dump( "QIn" );

        if ( iid.equals(Components.interfaces.nsIBrowserDOMWindow ) ||

             iid.equals(Components.interfaces.nsISupports ) )

        {

            return this;

        }

throw Components.results.NS_ERROR_NO_INTERFACE;

    },

openURI : function ( url, openerWin, where, context )

    {

        dump( "openURIn" );

        return openDialog( MY_PRODUCT_CHROME_URI, "_blank",

"all,dialog=no", url );

    },

isTabContentWindow : function ( win )

    {

        dump("isTabContentWindown");

        return false;

    }

}