Simon Strandgaard wrote: > >> Remember, since singleton class always exists for each object >> (virtually), 'class <<obj' is rather corresponds to class re-opening. >> > > > I am only little familiar with class re-opening.. > 'class << obj' by itself simple changes the current scope to the instance's singleton class. It doesn't change neither the instance itself, nor its inheritance structure. So I don't think this action should be reflected by any callback action. /kent