Mark on Views and The Single Responsibility Principle
It’s not just Cocoa. Every window system that ever lived suffers from something like this affliction. Either the system routes everything through the view (or the controller), which leaves a complex view looking like an old-fashioned switchboard operator, or instantiating a simple pane makes you create a whole slew of of handlers and delegates and thumgummies, and that drives programmers bats. Remember OpenDoc?