docs: public String getCopyModelReplaceId() {
  
          String result = null;
          if ((m_containerData.getMaxElements() == 1)
              && (m_overflowingElement != null)
              && (m_overflowingElement instanceof CmsContainerPageElementPanel)
              && (getFormerModelGroupParent() != null)) {
              result = ((CmsContainerPageElementPanel)m_overflowingElement).getId();
          }
          return result;
      }