Because of how most objects in Pathfinder "link" together in a very particular way (e.g. room-door), it doesn't lend itself very well to a general purpose copy/paste (e.g. two overlapping doors, you cannot connect both, how to you get them reconnected). In contrast, PyroSim just has a bunch of individual objects floating around, overlapping, etc. We painted ourselves into a corner in this respect because many of the elements you edit in Pathfinder snap in based on surrounding geometry and shipping them around as pieces is nonsensical from the data model's standpoint. We're working on it though. I know that not being able to copy can be very frustrating.