These classes implement a Finder-like hierarchical lists for the MetroWerks' PowerPlant framework. The use and workings of these classes is fully explained in my article in Apple's DEVELOP magazine issue 21.
If you don't have a copy of this magazine, then you can find it on the latest Developer's CD, Reference Issue or on the net on: ftp.info.apple.com
You can use this code in your applications free of charge. I'd be delighted if you could mention me and Wave Research in your About box. Thanks.
If you have any more questions, please do not hesitate to contact me.