@Deprecated(forRemoval = true)
  default @Nullable Icon getIcon(boolean isOpen) {
    if (ReflectionUtil.getMethodDeclaringClass(getClass(), "getIcon") == UsageGroup.class) {
      return null;
    }
    return getIcon(); // getIcon() is implemented
  }
@Deprecated(forRemoval = true)
  default @Nullable Icon getIcon(boolean isOpen)