code: @Override
      public boolean contains(final String text) {
          for (Tab tab : tabs) {
              if (text.equals(tab.getText())) {
                  return true;
              }
          }
  
          // not found in visible tabs, look in off-page
          return offPageContainer.contains(text);
      }
docs: Returns {@code true} if there's a tab with the specified text, {@code false} otherwise