How can you react to an event, if you aren't there by the time the event is occurring?
In a classic puremvc application you could, if you wanted/needed to, initialize the Facade on creationComplete and then in your mediator listen for applicationComplete, which is the last event dispatched during an application startup.
Look at this:
http://www.wietseveenstra.nl/blog/2007/02/understanding-the-flex-application-startup-event-order/On creationComplete or on applicationComplete you first initialize the PureMVC apparatus:
First the Facade, then the Commands, Proxies, Mediators.
In Fabrication ( as I understand it ) FlexApplicationFabricator is the first one that handles the FlexEvent.CREATION_COMPLETE, so if you'd trace it you'd see that the creationComplete that you're handling in your main app is called after the initializeEnvironment() in Fabricator, which does:
facade.registerCommand(FabricationNotification.STARTUP, ApplicationStartupCommand);
which does :
facade.registerMediator(new ApplicationMediator(app));
So your Mediator can't listen to anything happening before its own creation. It just isn't there, and it surely isn't God :)
Please correct me if I'm wrong.
Is it possible that you can't listen for FlexEvent calls with reactions?
You can. Try BUTTON_DOWN.