In ex parte appeal proceedings too, if a document is relied upon for the first time during the appeal proceedings and it is admitted because it is relevant, the case has normally been remitted to the department of first instance (see e.g. T 28/81, T 837/91, T 389/94).

Since the main purpose of the appeal proceedings is to review the decision of the department of first instance, the boards normally refer the case back if essential questions regarding the patentability of the claimed subject-matter have not yet been examined and decided on by the department of first instance. This applies to both ex parte and inter partes proceedings.

In T 229/90 the board stated that continuing commercial uncertainty cannot be in the general public interest. For this reason, the board must always balance this general public interest against the fundamental legal requirement that it should act only within its appellate role, as provided for by the EPC, and not step into the shoes of the department of first instance.