A "checkout" function is needed in Process Manager/Promapp

If two contributors edit a process at the same time, there is no indication of a conflict until you save and get an error saying you can't save because you're not in the current version. An automatic checkout when you start editing, and an error right away if someone else is already editing, would same much time, lost work and frustration with using Promapp. Even a manual checkout would be better than the current state.