private void buttonLogin_Click(object sender, RoutedEventArgs e)
 {
     var w = new WindowLogin();
     w.OnLoggedIn += (s, args) =>
     {
         api = args.Api;
         SaveAccount(GetUserKeyFilePath(), "user.anon.dat");
         Invoke(() =>
             {
                 CancelTransfers();
                 w.Close();
                 buttonLogin.Visibility = System.Windows.Visibility.Collapsed;
                 buttonLogout.Visibility = System.Windows.Visibility.Visible;
                 Title = title + " - " + api.User.Email;
             });
         InitialLoadNodes();
     };
     w.ShowDialog();
 }