private String getTitleSuffix() {
    ContentManager manager = ui.getContentManager();
    return switch (manager.getContentCount()) {
      case 0 -> null;
      case 1 -> {
        Content content = manager.getContent(0);
        if (content == null) yield null;
        final String text = content.getDisplayName();
        if (text != null && !text.trim().isEmpty() && manager.canCloseContents()) {
          yield ":";
        }
        yield null;
      }
      default -> ":";
    };
  }
private String getTitleSuffix()