Desktop Application size Problem

[Mohammed AMHEND]

Hi, I'm developing a Desktop Application for Windows with apache pivot; I
can't fixe the window size by using the setPreferredSize method

Actually the setPreferredSize method fixe, in my case, just the content of
the window but the window itself still resizable

here is my code :

*public class Main implements Application {
    private Window window;

    @Override
    public void startup(Display display, Map<String, String> map) throws
Exception{
        BXMLSerializer bxmlSerializer = new BXMLSerializer();
        window = (Window)bxmlSerializer.readObject(Main.class,
"window.bxml");
        window.setPreferredSize(800, 600);
        window.open(display);
    }

    @Override
    public void resume() throws Exception {
    }

    @Override
    public boolean shutdown(boolean arg0) throws Exception {
        return false;
    }

    @Override
    public void suspend() throws Exception {
    }

    public static void main(String[] args) {

        DesktopApplicationContext.main(Main.class, args);
    }
}*

can you help me ?