Gary I have a request about the way we use preference. And this is kind of really really important if we want to stop having spaghetti code. Instead of having the current situation ie MyTool>>doSomething .... Preferences useNewDiffTool ifTrue: [kjlhkjhjkh ] ifFalse: [nkjhkjkjhkj] and not been able to remove the preferences (or that the preference is just a configuration layer). I would like to have the preference made that way MyTool class>>useNewDiff MyTool class>> useOldDiff **NO REFERENCE TO PREFERENCE IN THE METHOD FLOW!!!! Preferences useNewDiffTool MyTool useNewDiff I really think that we can do it that way and this way we would have a much more object-oriented system Do you think that this is possible with polymorph? I think so. Stef