Hey Cliff, that was the most important, interessting and helpful explanation I have read in this forums so far! Thank's a lot, that helped me a lot!! Yeah!!!

Now I can go on building my world app ... 

How much of a heresy would it be to build an app with a set of Mediators with null view components in place of all the commands? You could even name them commands and put them in a directory where commands normally go in your source tree - but instead of extending Command simply extend Mediator.

Yes, that is what I am thinking about, too! I am very new to all this stuff, can anyone explain? I would love to hear more about that, because that is one of my biggest problems: when do I use Commands? It seems, that in most (if not all) cases, Mediators and Proxies would suffice.

[sorry for bad english, I'm german]