The first thing I did with PureMVC was implement a logging system for notifications (I modified the framework) ... so that when a notification occurs it is logged something like
Notification Raised : name : CHANGE_THE_THING, args : 1,2,3
> executing observer : 1 of 4
> executing observer : 2 of 4
> executing observer : 3 of 4
> executing observer : 4 of 4
/ Notification End
So ... when you switch this logging on, you can easily see where the application is at.