code: public void setOwner(ListenerOwner owner)
      {
          if (owner == null)
          {
              this.saveValue(m_recordOwnerCache);
              m_recordOwnerCache = null;
          }
          super.setOwner(owner);
          if (owner != null)
              this.retrieveValue();
      }
docs: Set the field that owns this handler.
  @param owner The field this listener was added to (or null if being removed).