In re C.O.S., 988 S.W.2d 760 (Tex. 1999) holds that there are three categories of rights and requirements used in determining whether error may be raised for the first time on appeal. See 988 S.W.2d at 765-767. the first set of rights are those that are considered so fundamental that implementation of these requirements is not optional and cannot, therefore, be waived or forfeited by the parties. See id. at 765; Marin v. State, 851 S.W.2d 275, 279 (Tex. Crim. App. 1993). The second category of rights are those that must be implemented by the system unless expressly waived. See In re C.O.S., 988 S.W.2d at 766; Marin v. State, 851 S.W.2d at 278-79. The third set of rights are those that the trial court has no duty to enforce unless requested. See In re C.O.S., 988 S.W.2d at 765; Marin v. State, 851 S.W.2d at 279. The law of procedural default applies to this last category. See In re C.O.S., 988 S.W.2d at 767 (quoting Marin v. State, 851 S.W.2d at 279).