The favorite application should be usable cross wiki

The scenario is the following:

A farm with multiple wikis, on which users are all on the main wiki.

Currently, even when the favorites application is installed on all the wikis of the farm, when adding a page to the favorites from the panel on a subwiki, the page is stored with a relative reference in the user profile (full name instead of prefixed fullname) and will not be identified correctly further on.

Expected result:

• it should be possible to be able to add favorites from subwikis in the list of favorites of a user on the main wiki
• ideally the application should need to be installed only on the wiki where the users are stored (so that the class is available), but this is not a strong requirement.