private static DialogResult MessageBox(MessageViewModel messageViewModel, BottomPanelButtons buttons)
    {
        var viewModel = new MessageWindowViewModel(messageViewModel, buttons);
        var window    = new MessageWindow(viewModel);

        window.ShowDialog();
        return(viewModel.DialogResult);
    }
 public MessageWindowViewModel(MessageViewModel messageViewModel, BottomPanelButtons buttons)
 {
     _messageViewModel = messageViewModel;
     // "this" is passed as the BottomPanelViewModel's IHasBottomPanel parameter:
     _bottomPanelViewModel = new BottomPanelViewModel(buttons, this);
 }