if a user edits a map and his session times out, map interface becomes partially unusable :
user can't save map, background image and links are not displayed and new elements can't be added.

even if the user logs in into another tab, new elements can't be added and map can't be saved.

3 problems here :

1. user loses all changes since last save;
2. map becomes ugly and controls mysteriously stop working;
3. information from map links still can be accessed after logging in with another session.

partial solution for 1. : find out whether user has auto-logout enabled and do keepalive requests (or do them anyway);
possible solution for 1. : allow user to log back in and submit the map changes;
possible solution for 2. : display some informative message, but do not discard map changes;
what to do with 3. : find out why information from map link macros can be accessed with a different sid