Is res judicata conclusive with respect to any claims relating to the cause of action?

In Connecticut, the doctrine of res judicata establishes that a prior judgment on a particular cause of action "is conclusive with respect to any claims relating to the cause of action which were actually made or might have been made." Corey v. Avco-Lycoming Div., 307 A.2d 155, 160 (Conn. 1972) (emphasis added). A judgment therefore does not preclude claims that could not have been made in the forum from which the judgment issues. As the Restatement explains, the general rule of claim preclusion "does not apply to extinguish the claim" in a second action where the "plaintiff was unable to rely on a certain theory of the case or to seek a certain remedy... in the first action because of the limitations on the subject matter jurisdiction of the courts." Restatement (Second) of Judgments 26(1)(c) (1982); see also id. cmt. (c) (noting that the general rule of claim preclusion "assum[es] that the jurisdiction in which the first judgment was rendered was one which put no formal barriers in the way of a litigant's presenting to a court in one action the entire claim," and stating further that "[w]hen such formal barriers in fact exist[] and [are] operative against a plaintiff in the first action, it is unfair to preclude him from a second action in which he can present those phases of the claim which he was disabled from presenting in the first").