docs: public void setOwner(ListenerOwner owner)
      {
          super.setOwner(owner);
          if (owner != null)
          {
              if (mainFieldName == null)
                  m_fldMain = this.getOwner().getReferenceField(m_FileToRead);
              if (fileKeyFieldName != null)
                  m_FileToRead.setKeyArea(m_FileToRead.getField(fileKeyFieldName));
              else
                  m_FileToRead.setKeyArea(m_FileToRead.getField(m_iFileKeyField));
          }
      }