Users observed when multiple users work in the same plan, changes will be saved for both of them. In order to not be undoing each other's amendments I would like to have a better understanding of how this works.
Saving a plan reloads some extra data (inc. tasks, shift pattern assignments and orders) in addition to the tasks data. Other data (e.g. items, production rates, sales orders, resources, resource groups, processes, plots, setup matrix, BOM, algorithms, etc.) is not reloaded.
The way Orchestrate handles data is different. Task related data (e.g. tasks properties, task attributes, pegging, etc.) is memory based and they can only be saved when clicking Save plan button. However, other data (e.g. Shift patterns and their assignments, item attribute values, order attrib values, product rates, etc.) is always saved directly into the database.
As long as you are dragging tasks on different views and resources (or the two tasks being dragged are not pegged or linked together), no edit conflict will take place. If they are dragging tasks from the same resource or view, then a message may appear from the error list as a edit conflict. You can resolve the edit conflict though, as a prompt appears with multiple options when you right click the edit conflict message from the Error List:
accept the other user's change
accept all timing changes made by the other user
re-apply my change
re-apply all my timing changes