public BrowserForm()
 {
   InitializeComponent();
   _windowManager = new WindowManager(this.tabControl);
   _windowManager.CommandStateChanged += new EventHandler<CommandStateEventArgs>(_windowManager_CommandStateChanged);
   _windowManager.StatusTextChanged += new EventHandler<TextChangedEventArgs>(_windowManager_StatusTextChanged);
 }
      public BrowserForm( string url){
          InitializeComponent();
          _windowManager = new WindowManager(this.tabControl);
          _windowManager.CommandStateChanged += new EventHandler<CommandStateEventArgs>(_windowManager_CommandStateChanged);
          _windowManager.StatusTextChanged += new EventHandler<TextChangedEventArgs>(_windowManager_StatusTextChanged);

          var br = this._windowManager.New();
          br.Url = new Uri(url,UriKind.Absolute);
          br.Navigate(url);
          
      }