private void ShowPreviewWindowExecute(object sender)
 {
     if (PreviewTemplateWindow == null)
     {
         PreviewTemplateWindow = new PreviewTemplateWindow()
         {
             DataContext = this
         };
         GeneratePreviewExecute(sender);
         PreviewTemplateWindow.Show();
         PreviewTemplateWindow.Closed   += (o, args) => PreviewTemplateWindow = null;
         App.Current.MainWindow.Closing += (o, args) => PreviewTemplateWindow?.Close();
     }
     else
     {
         PreviewTemplateWindow.BringIntoView();
     }
 }
 public override Task <bool> OnGoNext(DefaultStepConfigurator defaultStepConfigurator)
 {
     PreviewTemplateWindow?.Close();
     IoC.Resolve <MailComposer>().Template = Template;
     return(base.OnGoNext(defaultStepConfigurator));
 }
 public override bool OnGoPrevious(DefaultStepConfigurator defaultStepConfigurator)
 {
     PreviewTemplateWindow?.Close();
     return(base.OnGoPrevious(defaultStepConfigurator));
 }