The addition of new dependent claims which do not correspond to any claims as granted is not appropriate or necessary to overcome a ground for opposition and therefore impermissible (see e.g. T 794/94, T 674/96, T 24/96). As explained in T 829/93 and T 317/90, the addition of a dependent claim is not a response to an objection that the claimed subject-matter is not patentable because it neither limits nor amends the subject-matter claimed in the relevant independent claim. The fact that dependent claims can serve as an important safety net should the corresponding independent claim ultimately be refused does not render it legitimate to add them to a remaining, broader independent claim in opposition proceedings.
In T 711/04, the board took the view that the decision in G 9/91 (OJ 1993, 408) did not answer the question to what extent a patent proprietor may amend a non-opposed claim in opposition or appeal proceedings. Rather, it merely set out the legal and factual framework for substantive examination of the patent in suit. In accordance with those principles, not even the patent proprietor could propose amendments because the subject-matter of a non-opposed claim was not the subject of an "opposition" within the meaning of Art. 101 and Art. 102 EPC 1973 (new Art. 101 EPC combines Art. 101(1) and (2) EPC 1973 with Art. 102(1) to (3) EPC 1973; R. 82 EPC) or "proceedings" within the meaning Art. 114 and Art. 115 EPC. The Enlarged Board of Appeal had also found, however, that this basic principle was not directly applicable where the only subject-matter outside the specified scope of the opposition were dependent claims which had to be regarded as implicitly covered (see point 11 of the Reasons). This exception for sub-claims was, the board found, entirely justified by the fact that a sub-claim combined with a main claim and requested as a new main claim had to be examined as to its form and substance in order to ascertain whether or not the combination of the claims had extended the protection sought. This also showed that the theoretical legal construct underlying the G 9/91 decision, i.e. that there were no proceedings within the meaning of Art. 114 or Art. 115 EPC, was untenable in the case in hand. A patent proprietor wishing to limit the patent to the subject-matter of a non-opposed sub-claim had to combine that sub-claim with the corresponding main claim. The non-opposed sub-claim was inevitably amended as a result, even if the amendment might appear to be a mere technicality.