A global user cannot change its own user directly display in a domain based subwiki

A good use case example is myxwiki.org.

When a user try to modify the user directly an ajax request is executed to its user profile page, unfortunately for global user doing that on a subwiki which have a difference domain (www.myxwiki.org vs test.myxwiki.org) this is blocked by the browser with a CORS policy error.

I also I have doubt on whether this really take into account the wiki for which the modification was asked or if it modifies all wikis.

See https://forum.xwiki.org/t/myxwiki-user-directory-failed-to-save-the-page/10365/10 for an example.