Hi devs, I recently created http://jira.xwiki.org/jira/browse/XWIKI-5149, this issue is due to the fact that XWikiGroupServiceImpl#listMemberForGroup is splitting the value of the "member" field based on white space and comma. That does not make sense IMO and makes impossible to have a user with a white space (and comma which is less common) in its name for a very bad reason. Also the name of the field is "member" and not "members". Last reason is that i think in all other places we don't take this value as a list. Note that this bug is mainly a pain for authenticators where you have to remember the real name of the user and have some collision handling to support use case users "somename" and "some name" coming for an external authentication server in which theses are two different users. WDYT ? Here is my +1. -- Thomas Mortagne