Sub-Sub-Window

Hello
I want to create sub window from sub window.
When I create a sub window from main window then all fine:

// any strings of code
        final Window window = new Window();

        setMainWindow(window);

// any strings of code

        Button open2SubWindow = new Button("New Win");
        open2SubWindow.addListener(new Button.ClickListener() {
            
            @Override
            public void buttonClick(ClickEvent event) {
                // TODO Auto-generated method stub
                Window sub2window = new Window("My Sub Window");
                window.addWindow(sub2window);
                sub2window.setModal(true);
            }
        });
        window.addComponent(open2SubWindow);

And I recive a sub window.
When i create sub window from sub window then i reciven’t sub window:

        // any strings of code
        mywindow = new Window(windowcaption);
        mywindow.center();
        mywindow.setWidth("700px");
        mywindow.setHeight("500px");
        //mywindow.setModal(true);
        window.addWindow(mywindow);
        // any strings of code

        Button openSubWindow = new Button("New Win");
        openSubWindow.addListener(new Button.ClickListener() {
            
            @Override
            public void buttonClick(ClickEvent event) {
                // TODO Auto-generated method stub
                Window subwindow = new Window("My Sub Window");
                mywindow.addWindow(subwindow);
                subwindow.setModal(true);
            }
        });

How can I make sub window from sub window? Is it imposible?

It’s not possible. Only the main window can have subwindows; this is made explicit in Vaadin 7 where you can only add subwindows to UI instances (“main windows” in Vaadin 6)

Thanks a lot!