Bill,
When you are working with the class in the VCX you are doing just that working with your sublcass of the kBizObj. When you drop it on a form you are working with an instance of the class or rather an object. The reason you don't see any of the code is because it belongs to the class. The instance on the form has inherited it and if you don't add any new code to the method in question then anything you added in the class will still work.

This allows you to create the generic code that the class needs to work anywhere and at the same time leaves you free to customize the class when you drop it on a form. Just use the DoDefault() keyword, or other options, if you want to add custom code and get the original behavior.

I hope this helps,
Bill