A Week in Matrix

A user accidentally writes in the room of a Matrix space, resulting in every member of that space getting a notification. Matrix spaces are just regular rooms, and the fallback for old clients which don't support spaces is to render them as completely regular chat rooms. On the other side, new clients that do support spaces have very confusing UI when people start chatting in them, because that's not supposed to happen. (Yet, most clients don't adjust the room permissions in spaces to disallow people to chat in there. That would be too easy.)