I have been using Visio for a few days now and I'm frustrated because I can't edit my UML sequence diagram a bit without the whole thing falling apart. Say I have it already nicely done and I want to add an alt box. When I shift the whole thing down, some of the activation bars and message arrows are already anchored. So the whole diagram becomes a mess. I can't select a whole group of items and move them because this will screw up the relationships, anchoring, connectors within them. What settings do I adjust to avoid this from happening?