was a substantive addition in the 1955 codifi cation of the Probate Code, which was otherwise predominantly nonsubstantive. R. Dean Moorhead, Forward to Tex. Rev. Civ. Stats. Vol. 17A, Probate Code at IV-VI (West 1956) ("95% of the Code consists of a reenactment of the former statutes” but in addition to "other important changes and additions,” “[t]he period for obtaining a bill of review has also been set at two years....”); see also Probate Code Institute, 18 Tex. BJ. 373, 374 (1955) ("Some Texas courts hold that a bill of review can be had at any time within 4 years, while other courts hold that the period is 2 years. Section 31 eliminates this conflict and harmonizes bills of review with certiorari by adopting the 2-year period.”); Cluck v. Hester, 521 S.W.2d 845, 848 (Tex. 1975) (<HOLDING>); Lechow v. Moore, 524 S.W.2d 614, 615 n. 1
recognizing that appeal and certiorari were concurrent and alternative remedies and explaining that appeal to the district court was a true trial de novo whereas certiorari reviews the action of the probate court for errors committed by that court  de novo but the issues are confined to errors of the county court specifically set forth in the application for the writ of error holding that the court reviews an administrators decision de novo when substantial procedural errors cause the beneficiary substantive harm recognizing that this court reviews de novo the trial courts interpretation and application of a statute to undisputed facts holding that the proper review for the trial courts application of the law is de novo recognizing that appellate court reviews questions of law de novo