Thanks for your answer.
My example isn't very clear. It is not about those specific notifications. The thing that's nasty for my, is that all mediators from inactive ViewStack assets keep receiving their notifications. Maybe the only valid solution to this problem is something like removing the mediator when its view is not active.

Thanks for the Slacker example.
There can be a problem by using a ViewStack however.
Imagine each views Mediator in a ViewStack listens for an ApplicationFacade.ON_NEXT and ApplicationFacade.ON_PREVIOUS notification.
When I send such a notification through the application, ALL mediators react, because the ViewStack only HIDES the not selected views.

A simple check on the views visibility a the start of the handleNotification method doesn't solve this problem. I just want the mediator of the ACTIVE view to react on notifications.

Anyone any ideas about a simple solution?