How to reproduce
- Create a group with user A and B as member
- Enable the EP tool for the group
- With user A, open the EP tool and create an entry. In the entry create some parts
- Login with a second browser with user B and open the EP tool in the group, open the same entry
- With user A, delete a part
- With user B, try to edit the part that has been deleted by user A
- => NOK RS
Expected behaviour: a message that tells the user that this part has been deleted by someone else.
I did not test what happens when reordering things, if this messes up things as well, or adding some parts by both users at the same time. Ideally a lock would be made on a single part and moving parts around would be pushed via a multi-user event to all users who are collaborating on a page.
Making it possible to concurrently edit a page would be a killer feature for the long-term usage of the editor as a collaborative page editor. However, for now this is not a mandatory requirement, we implement it only if feasible with acceptable amount of work. For the group EP a temporary solution could be to simply put a GUI lock to the entire page editor so that only one person at any time can edit a page.