In Finger v. Southern Refrigeration Services, Inc., 881 S.W.2d 890 (Tex. App.--Houston 1st Dist. 1994, writ denied), the court discussed the application of collateral estoppel, not res judicata. See Finger, 881 S.W.2d at 895.
Noting that "the doctrine of collateral estoppel applies only to issues actually litigated in the earlier proceeding," the court held that collateral estoppel did not bar the claims of a plaintiff against whom the trial court had erroneously granted a directed verdict. Id. at 895-96.
The court went on to state, "even if collateral estoppel applied in this case, we have the discretion to refuse to apply it if it would be unfair." Id. at 896.