Just remember that in a control's init(), the form doesn't exist yet -- containers in VFP instance from the inside out. If you need to reference the form, then in the form init() I would feed all the objects to the preference engine, like this

*-- Form Init()
FOR EACH oControl IN THIS.Controls
  oPreference.Execute( oControl)
ENDFOR

This method might be best since it requiores code in one place only, and the interface control classes don't need to know about the preference engine, and that makes them more reusable.