In T 809/95, the opponents maintained that the claim at issue did not contain all the features which a skilled person would recognise as essential from the second priority document, with the result that the claim was directed to another invention. The board established, however, that the features which the opponents thought were missing were not connected in any recognisably close way with the problem put forward in this priority document. This problem was not solved by the missing features, but by other features, all of which could be found in the claim. Thus the subject-matter of this claim was entitled to claim the second priority.
In T 576/02 the board pointed out that the omitted feature was even less essential in that it did not even appear in the independent claims of the priority document, which by definition specified all the essential features of the invention.
In T 515/00 the appellant had argued that features pertaining to hardware components relating to the printing process were no longer present in the claim and that there was no basis in the priority document for the deletion of these features. The board referred to G 2/98 (OJ 2001, 413, point 8.3 of the Reasons), in which the Enlarged Board had warned against an approach whereby a distinction was made between technical features which were related to the function and the effect of the invention and technical features which were not. Priority could not be acknowledged if a feature was modified or deleted, or a further feature was added. The board further noted that a claim passed the priority test if its subject-matter could be derived from the previous application as a whole. It followed that comparing the claim with the corresponding claim of the previous application was not a valid approach to performing the "priority test". The priority test was basically a disclosure test in which the skilled reader could use common general knowledge. If, in the description of the previous application, a distinction was made between features that were essential for the performance of the invention and features which were not, the latter could be deleted from the subject-matter of a claim without losing the right to priority. The omitted hardware components were nowhere presented as essential features in the priority document's description. The skilled reader would not have any reason to assume that they were essential merely because they were present in claim 1 of the priority document. This decision was followed in T 321/06.