>One other question on sub-classing:
>If you have a sub-class that modifies a property from the default value of the baseclass, and then later that property is removed from the baseclass, that property no longer exists in the sub-class. You don't get any error or any indication that the property no longer exists in the base class, until you try to reference it in code for your sub-class. I would have thought that the sub-class property would have just become a new property belonging only to the sub-class. Is this correct functionality?

The property should probably remain hanging and be disregarded. You can try out what happens by simply adding a line to the Properties memo - the unregistered properties are ignored. To register a property to be a new one for a class, it needs an entry in Reserved4. Just add one in the editor and see what happens in the Reserved4 (or was it 3?).

You may actually write a checker, which would scan the properties memo for any properties which don't exist in the parent class, and have them added in the ReservedX, and recompile the class in the end.