String () { 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().length() > 0 && manager.canCloseContents()) { yield ":"; } yield null; } default -> ":"; }; }