docs: protected List<CmsContainerPageElementPanel> getAllContainerPageElements(boolean includeGroupContents) {
  
          List<CmsContainerPageElementPanel> elemWidgets = new ArrayList<CmsContainerPageElementPanel>();
          for (Entry<String, org.opencms.ade.containerpage.client.ui.CmsContainerPageContainer> entry : CmsContainerpageController.get().getContainerTargets().entrySet()) {
              Iterator<Widget> elIt = entry.getValue().iterator();
              while (elIt.hasNext()) {
                  try {
                      org.opencms.ade.containerpage.client.ui.CmsContainerPageElementPanel elementWidget = (org.opencms.ade.containerpage.client.ui.CmsContainerPageElementPanel)elIt.next();
                      elemWidgets.add(elementWidget);
                      if (includeGroupContents && (elementWidget instanceof CmsGroupContainerElementPanel)) {
                          List<CmsContainerPageElementPanel> groupChildren = ((CmsGroupContainerElementPanel)elementWidget).getGroupChildren();
                          elemWidgets.addAll(groupChildren);
                      }
                  } catch (ClassCastException e) {
                      // no proper container element, skip it (this should never happen!)
                      CmsDebugLog.getInstance().printLine(
                          "WARNING: there is an inappropriate element within a container");
                  }
              }
          }
          return elemWidgets;
      }