>So you are saying that if the base of the class was SESSION I wouldn't have to worry about calling methods of this class/object from any procedure (even private DS form)?
>
>UPDATE. Even after changing the base class from CUSTOM to SESSION, the methods of the class seem to be working in private DS.

All the rules still apply - unless you create it as a session class with its own datasession (.datasession=2). It is so, by default in VFP9 - not quite sure for the previous versions. You can still have a session class with .datasession=1 (meaning "use default DS", which is not the default value of this property) (yes, it's clear to me too :).

The difference here is that a session class will create its own session - which is usually its purpose, you want to isolate a process and the tables it uses, you make it run within a session class, or in a form with a private DS. If you create an object of any other class (not session, not form, not formset), it will be created and its code will run in the creator's DS (and the other rules will apply as per the Wiki page).