Hooks

Make sure there is a full set of hooks and callbacks in the VBA style. Users can then override them to their hearts content.

Object.Validation - returns a list of errors.

Object.New - called on creation of a new object. Enables default values to be added.

Object.Save - called before persisting enabling values to be calculated.

Needs some more work building up a full list of call backs.

Should all forms have call backs?