void OnLoaded(object sender, RoutedEventArgs e)
        {
            Dispatcher.BeginInvoke(new Action(() => {
                UpdateButtonState();

                foreach (UIElement child in EntryPanel.Children)
                {
                    TextBox box = child as TextBox;
                    if (box != null && box.Visibility == System.Windows.Visibility.Visible)
                    {
                        box.Focus();
                        box.SelectAll();
                        break;
                    }
                    else
                    {
                        PasswordControl pswd = child as PasswordControl;
                        if (pswd != null && pswd.Visibility == System.Windows.Visibility.Visible)
                        {
                            pswd.SelectAll();
                            break;
                        }
                    }
                }
            }));
        }
        private void OnPasswordBoxGotFocus(object sender, RoutedEventArgs e)
        {
            PasswordControl box = (PasswordControl)sender;

            box.SelectAll();
        }