Application.getWindow() API

In the Vaadin API
Application.getWindow()
method has code example like this:

// If we already have the requested window, use it
        Window w = super.getWindow(name);
        if (w == null) {
            // If no window found, create it
            w = new Window(name);
            // set windows name to the one requested
            w.setName(name);
            // add it to this application
            addWindow(w);
            // ensure use of window specific url
            w.open(new ExternalResource(w.getURL().toString()));
            // add some content
            w.addComponent(new Label("Test window"));
        }
        return w;

what does this part of the example means?

            // ensure use of window specific url
            w.open(new ExternalResource(w.getURL().toString()));

In order to open the new window, shouldn’t the
open
method be called for the parent window, not the new window instance?

-Timo

It changes the browser window to point to the URL dedicated for the server-side Window -object.

Also see this
http://vaadin.com/web/joonas/wiki/-/wiki/Main/Supporting%20Multible%20Tabs
.