private void ToggleDeclineMenu(object sender, RoutedEventArgs e)
 {
     //**********************************************************************************************************************
     // When call Decline button is Popup pressed over call window. It will show the messages for decline a call.
     //**********************************************************************************************************************
     if (_viewModel != null)
     {
         _viewModel.ShowDeclineMenu = !_viewModel.ShowDeclineMenu;
         ArrowBtn.Focus();
     }
 }