c) Decisions doubting cross-procedural res judicata effect 

In T 2084/11 the appellant (opponent) had argued that the invention's reproducibility was res judicata, a final decision having already been taken on the parent application. The board noted that the EPC did not mention res judicata, let alone regulate its applicability in the context of separate proceedings on parent and divisional applications or any resulting patents. EPO proceedings on a divisional were essentially independent of those on its parent (see T 1254/06). The board therefore doubted that a final decision taken in opposition appeal proceedings (here revocation of the patent) could have any "cross-procedural" res judicata effect at all on separate opposition (or opposition appeal) proceedings concerning a patent granted on a divisional. T 167/93 had already said that res judicata, whilst a generally recognised principle, was of extremely narrow scope and would only "involve something" where (amongst other criteria) "the issues of fact are the same". But it had said nothing about any "cross-procedural" application. In the case in point, the board anyway took the view that the above criterion from T 167/93 was clearly not fulfilled, because the subject-matter (the "something" in the sense of T 167/93) requiring the division's or board's decision was not the patent granted for the parent application; rather, it was the divisional-derived patent and whether the requests submitted were legally sustainable in view of the objections raised, and – in contrast to T 51/08 – the requests (sets of claims) for decision in the two sets of proceedings were also not identical. Moreover, the underlying facts were different since further evidence had been submitted. The board's conclusion was that in the case in hand the appeal decision on the parent patent could have no res judicata effect in the opposition (or opposition appeal) proceedings as regards the reproducibility of the divisional-derived patent in suit.