code: void openSitemapEditor() {
  
          CmsObject cms = A_CmsUI.getCmsObject();
          String siteRoot = cms.getRequestContext().getSiteRoot();
          if (CmsStringUtil.isNotEmptyOrWhitespaceOnly(siteRoot)) {
              String path = getPath(cms, A_CmsUI.get().getHttpSession());
              if (path != null) {
                  try {
                      CmsAppWorkplaceUi ui = CmsAppWorkplaceUi.get();
                      if (ui.beforeViewChange(
                          new ViewChangeEvent(ui.getNavigator(), ui.getCurrentView(), null, APP_ID, null))) {
                          CmsResource res = cms.readResource(CmsADEManager.PATH_SITEMAP_EDITOR_JSP);
                          String link = OpenCms.getLinkManager().substituteLink(cms, res);
                          A_CmsUI.get().getPage().setLocation(link + "?path=" + path);
                      }
                      return;
                  } catch (CmsException e) {
                      LOG.debug("Unable to open sitemap editor.", e);
                  }
              }
          }
          Notification.show(CmsVaadinUtils.getMessageText(Messages.GUI_SITEMAP_NOT_AVAILABLE_0), Type.WARNING_MESSAGE);
      }
docs: Opens the sitemap editor for the current site.<p>