This is something we hear a fair amount and will be looking into it. The issue is how things are tied together on our back end. We tie flights to missions to maps and if changes the mission are made then things would be thrown off. If we were to add support for this it would really end up essentially deleting the old mission and creating a new one. This would be fine for some users but would break things for others. Doing the edits and syncing it is no problem but issues arise when considering users that would be editing something that has already been flown 5 times. That is why we just create a new mission based on edits because that is how it would be treated anyway.