Objective-C/Cocoa: Proper design for delegates and controllers

Question

Consider the following common situation:

You have some MainView in your Cocoa application, loaded from a NIB, which is controlled by a MainViewCon

Answer 1

We implemented a tricky "Data"-object which controlls pretty much everything. It checks if there are changes and keeps all globals updated.

When creating new instances I refer to the Data class like this:

[[Button alloc] initWithData:data]];

Where data is the singelton Data-class. Now we can check if there are changes needed to react on.

I admit, it still requires referencing like you described though. There doesn't seem to be a simple parent reference imbedded.