Xamarin Forms: WhenActivated not being fired reactiveui for viewmodel

I can't understand why the WhenActivated func is not fired for a Xamarin Forms application. The application has a LoginViewModel and a LoginView

• LoginView: inherits from ContentPageBase which itself derives from : ContentPage, IViewFor which I think is expected
• LoginViewModel: ReactiveObject, IRoutableViewModel, ISupportsActivation

Here's the sample application code.

The first view LoginView is loaded as expected. However, I would ideally like to load services and setup ReactiveUI.

Any ideas?

Source code

thanks