b) Decisions leaving open the question of cross-procedural res judicata effect 

In T 1643/10 the board left open the question of whether, or to what extent, decisions regarding a parent or a sibling application represent res judicata for a divisional application. For the board in T 1666/14 too, there was ultimately no need to answer this question because the claims at issue in the examination appeal proceedings brought before it in relation to the divisional application differed from those decided on in the earlier opposition appeal proceedings concerning the parent application. It nevertheless took the view that, where decisions had been taken on a parent application in both examination appeal and opposition appeal proceedings, only the latter decision could, if at all, have binding effect on the relation between the parent and divisional application. See also T 2145/11, T 1870/16 and T 1270/20, in which the boards similarly held there could be no res judicata because the claims were not identical.