Using ancestors and descendants – PB Docs 2019

descendant objects

In PowerBuilder, an object class can be inherited from another
class. The inherited or descendant object has all the instance
variables, events, and functions of the ancestor. You can augment the
descendant by adding more variables, events, and functions. If you
change the ancestor, even after editing the descendant, the descendant
incorporates the changes.

Instantiating

When you instantiate a descendant object, PowerBuilder also
instantiates all its ancestor classes. You do not have programmatic
access to these ancestor instances, except in a few limited ways, such
as when you use the scope operator to access an ancestor version of a
function or event script.