In Barr v. Resolution Trust Corp. ex rel. Sunbelt Fed. Sav., 837 S.W.2d 627, 628 (Tex. 1992), the Texas Supreme Court adopted the "transactional" approach to res judicata, holding, "A subsequent suit will be barred if it arises out of the same subject matter of a previous suit and which, through the exercise of diligence, could have been litigated in a prior suit." Id. at 631. "A determination of what constitutes the subject matter of a suit necessarily requires an examination of the factual basis of the claim or claims in the prior litigation." Id. at 630. "It requires an analysis of the factual matters that make up the gist of the complaint, without regard to the form of action." Id. "Any cause of action which arises out of those same facts should, if practicable, be litigated in the same lawsuit." Id. In Barr, the Texas Supreme Court held res judicata applicable where the issues in two claims "formed a convenient trial unit," and separate lawsuits on each claim "would require significant duplication of effort of the court and the parties involved." 837 S.W.2d at 631.