Caliburn Micro GoBack to previous page instance WinRT

问题

I am using Caliburn.Micro.Core.2.0.1 on Windows Phone 8.1 (WinRT) application

All my ViewModels extends Screen as the base.

In my MainView(Model) I am able to navigate to a SettingsView(Model) with CM's INavigationService using

private readonly INavigationService _navigationService;
public void Navigate()
{
    _navigationService.NavigateToViewModel<SettingsViewModel>(_param);
}

Then using the Hardware Back Button or

public void GoBack()
{
   _navigationService.GoBack();
}

I can navigate back to the MainView(Model).

It works; however, it does not work as I expected or wanted it to work.

When the GoBack (or Back button) is called, it generates a new instance of MainView(Model). I want it to return to the navigated from instance of MainView(Model).

I tried registering MainViewModel as a Singleton, this makes the ViewModel a singleton (and introduces some interesting issues); but the View is still recreated.

Any idea how to get the navigation to go back to the navigated from instance?