support multiple sessions behind the same in-room user
However, if the bare JID firstname.lastname@example.org of the present occupant matches the bare JID of the user seeking to enter the room, then the service SHOULD allow entry to the user, so that the user has two (or more) in-room "sessions" with the same roomnick, one for each resource. If a service allows more than one occupant with the same bare JID and the same room nickname, it MUST route in-room messages to all of the user's resources and allow all of the user's resources to send messages to the room; it is up to the implementation whether to route private messages to all resources or only one resource (based on presence priority or some other algorithm); however, it is RECOMMENDED to route to all resources.
When som user joins a Room, if the same bare jid is already connected, use the same user for both jids
(from redmine: created on 2014-07-13, duplicates #3173 (closed))