Amendments must be examined fully for compatibility with the EPC. Thus, where the respondents (opponents) first raise an objection under Art. 100(b) EPC during the appeal proceedings to an amended claim, the appellants cannot not refuse permission to discuss the new ground (T 27/95).
Art. 101(3)(a) and R. 82 in conjunction with R. 100(1) EPC (former Art. 102(3) EPC 1973 in conjunction with R. 66(1) EPC 1973) confer wide powers upon the boards to consider all possible objections under the EPC, pleaded or not pleaded, that might arise from an amendment of the claims originally filed. In case objections concerning the requirements of Art. 123(2) EPC are not expressly pleaded under R. 76(2)(c) EPC (former R. 55(c) EPC 1973), but form part of the opposition division's decision, the objection under Art. 123(2) EPC form part of the legal framework of the decision under appeal and the appellant cannot not rely on G 10/91 for its request not to admit this ground into the appeal proceedings (see T 922/94).
The fact that amendments have been made to a claim in the course of the opposition proceedings does not allow an opponent to raise an admissible objection under Art. 123(2) EPC at the appeal stage in the absence of the patentee's agreement, if such objection results from an amendment made before grant and has not been originally raised as a ground for opposition under Art. 100(c) EPC pursuant to R. 55(c) EPC (T 693/98).
The introduction of a feature into an independent claim, which feature was present in the claims and in the description as granted, could not be considered as an amendment which legitimated the admittance of Art. 100(b) EPC as a fresh ground of opposition, which required that a European patent as a whole had to disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art (T 1053/05; cf. T 739/08).