Kernrechtsfrage
Whether the appeal court violated the appellant's right to be heard by deciding on necessary joinder without prior submissions.
Extrahierter Entscheid
No. The joinder question was a legal issue the court could raise ex officio; the parties had already addressed the relevant facts and legal context.
Extrahierte Begründung
Under jura novit curia, the judge need not submit legal principles to discussion unless relying on an unforeseeable rule. The appellant had itself touched on the issue and the sister's position was not shown to require advance consultation.