This is a known / deliberate limitation. In a previous implementation the editing area width was adjusted to leave space to show all users typing on the same line. This was creating a very ugly and annoying UI flickering. I preferred to fix that UI flickering even though it introduced this (temporary) limitation. We need to find a way to show all user indicators without any UI flickering. Of course, the best option is to show the user care inline, inside the editing area, but this is not trivial but rather complex. I think this is something that the underlying WYSIWYG editor library should provide, not something that we should implement and maintain.