docs: public int findElement(Object bookmark, int iHandleType)
      {
          if (bookmark == null)
              return -1;
          int iTargetPosition = m_gridBuffer.findElement(bookmark, iHandleType);
          if (iTargetPosition == -1)
              iTargetPosition = m_gridList.findElement(bookmark, iHandleType);
          return iTargetPosition;   // Not found
      }