Art. 59 BV; intercantonal scope of venue protection and joinder of heirs; the constitutional venue guarantee may be invoked only in an intercantonal setting and not against an intra-cantonal district forum. Where a claim is directed jointly against all heirs of a deceased person and an enforceable judgment is sought, the action must be brought against all joint defendants; if the complaint of some defendants is upheld, the annulment must extend to all co-defendants owing to the unitary character of the dispute and the need for consistent enforceability.