Event propagate
This event is called after a modification has been done to properties in a class. It allows a development partner to assign values to other properties if necessary.
In this code, the development partner can assign values to other properties of the current instance (this).
The following variables are available in the context:
CURPRO variable gives the name of the property modified which triggers the propagate action.AINDEX variable gives the current index if the property is an array. This is available only on some system classes. No variable arrays exist on persistent or normal classes.this is the current instance where the property is located.this.snapshot is the instance where the initial values of the properties are stored.