docs: @Override
      protected String createDialogHtml(String dialog) {
  
          StringBuffer result = new StringBuffer(1024);
  
          // create widget table
          result.append(createWidgetTableStart());
  
          // show error header once if there were validation errors
          result.append(createWidgetErrorHeader());
  
          int n = 1;
  
          // initialize the cache object to use for the dialog
          CmsFlexController controller = (CmsFlexController)getJsp().getRequest().getAttribute(
              CmsFlexController.ATTRIBUTE_NAME);
          CmsFlexCache cache = controller.getCmsCache();
  
          // widgets to display
          if (cache.cacheOffline()) {
              n = 2;
          }
          if (dialog.equals(PAGES[0])) {
              // create the widgets for the first dialog page
              result.append(dialogBlockStart(key(Messages.GUI_FLEXCACHE_LABEL_CLEAN_BLOCK_0)));
              result.append(createWidgetTableStart());
              result.append(createDialogRowsHtml(0, n));
              result.append(createWidgetTableEnd());
              result.append(dialogBlockEnd());
          }
  
          // close widget table
          result.append(createWidgetTableEnd());
  
          return result.toString();
      }