Collab thread editing

I don't know whether this can be done but I don't think so, like Supersebi3 explained above.

I don't think this is a good idea, personally. What if someone keeps changing something in a thread, that you don't want? It would create unnecessary drama and people would have no clue what you were originally talking about. Plus, I don't feel like there would ever be a time for this to be needed. I cannot come up with a reason for when there would need to be 2 people creating the same thread.