New Post: ActionMessage Not in Namespace

Ok - I have the bootstrapper working. I had to make the constructor public instead of static and call base(true). Then inside the constructor make a call to base.Start().

        public AppBootstrapper() : base(true)
        {
            --- other startup code
            Start();
         }

Then, in the OnStartup override, make a call to DisplayRootViewFor...

        protected override void OnStartup(object sender, System.Windows.StartupEventArgs e)
        {
            // do custom code here which you want to run on startup
            DisplayRootViewFor<MainWindowViewModel>();
            base.OnStartup(sender, e);
        }

So, back in action and the XAML markup for cal:Message.Attach now works with Blend and the VS designer. BTW, the namespace for using cal: uses Platform:

xmlns:cal="clr-namespace:Caliburn.Micro;assembly=Caliburn.Micro.Platform"