I'm developing a WPF app using MVVM. Most of my views have only xaml markup and nothing (except default boilerplate) on code behind.

All except one view that I use adorners to "blacken" the screen when I want to make the whole screen disabled.

    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        //todo: transfer to modelview
        contentAreaAdorner = AdornerLayer.GetAdornerLayer(contentArea);
        waitingAdorner = new WaitingAdorner(contentArea);
    }

Is that ok? Or is there a better way to implement this in my viewmodel?