Critical bug with document window tab sort

public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);

            WebBrowser b = new WebBrowser();
            b.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(b_DocumentCompleted);
            DocumentWindow dw = new DocumentWindow(dockManager, "test 1",
                    "test 1", null, b);
            dw.Activate();
            b.Navigate("http://www.actiprosoftware.com/");

            b = new WebBrowser();
            b.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(b_DocumentCompleted);
            dw = new DocumentWindow(dockManager, "test 2",
                    "test 2", null, b);
            dw.Activate();
            b.Navigate("http://www.actiprosoftware.com/");

            b = new WebBrowser();
            b.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(b_DocumentCompleted);
            dw = new DocumentWindow(dockManager, "test 3",
                    "test 3", null, b);
            dw.Activate();
            b.Navigate("http://www.actiprosoftware.com/");
            
        }

        void b_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
        {
            DocumentWindow w = (DocumentWindow)((WebBrowser)sender).Parent;
            w.Text = e.Url.ToString();
        }
    }

        /// <summary>
        /// Creates an instance of the <c>DockForm</c> class.
        /// </summary>
        public DockForm() {
            //
            // Required for Windows Form Designer support
            //
            InitializeComponent();

            // Set the menu color scheme
            mainMenu.ColorScheme = WindowsColorScheme.VisualStudio2005;

            // Select the first item
            if (toolWindowPropertyGridComboBox.Items.Count > 0)
                toolWindowPropertyGridComboBox.SelectedIndex = 0;
            if (dockManagerPropertyGridComboBox.Items.Count > 0)
                dockManagerPropertyGridComboBox.SelectedIndex = 0;

            // Create documents
            this.CreateTextDocument(null, "This is a read-only document.  Notice the lock context image in the tab.", true).Activate();
            this.CreateTextDocument(null, null, false).Activate();

            string[] urlStrings = new string[] { "http://www.actiprosoftware.com/", "http://www.microsoft.com/", "http://www.codeproject.com/" };
            for (int i = 0; i < 3; i++)
                this.CreateWebBrowserDocument("Browser" + i, urlStrings[i]);

            // Set the size for screenshots
            // this.Size = new Size(408, 377);

        }

        private void CreateWebBrowserDocument(string name, string urlString)
        {
            WebBrowser b = new WebBrowser();
            b.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(b_DocumentCompleted);
            DocumentWindow dw = new DocumentWindow(dockManager, name, name, null, b);
            dw.Activate();
            b.Navigate(urlString);
        }

        private void b_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
        {
            DocumentWindow w = (DocumentWindow)((WebBrowser)sender).Parent;
            w.Text = e.Url.ToString();
        }