//Navigation
            System.ComponentModel.BackgroundWorker worker = new System.ComponentModel.BackgroundWorker();
            worker.DoWork += delegate { initNavigation(); };
            worker.RunWorkerCompleted += delegate { initNavComplete(); };
            worker.RunWorkerAsync();


 public void showNavWindow()
        {
            ShowNavWindowCallback cb = new ShowNavWindowCallback(NavigationWindow.Show);
            this.Invoke(cb);
        }


        private void button1_Click(object sender, EventArgs e)
        {
            showNavWindow();
        }