Hi guys While I prefer sharedPool over pool dictionary and I like what andreas did back then. there are still places for improvements. If you file out a category with a pool and a class using it. If the pool is not created first, then the system automatically add a 'private' (pool named 'private') to the class the problem is that such pool is an empty dictionary and not a shared pool Gorgeous :) We will get there when we will start to surround the classBuilder and rewrite it from scratch. Stef