Hi devs ! In order to fix http://jira.xwiki.org/browse/XWIKI-2900, I have some proposals to you. The problem is : the Inclusion of groups in groups aren't taken into account when querying user memberships. Let suppose we have the following use case: User 1 inside the Goup A Group A inside the Group B The actual behaviour of XwikiGroupService# getAllGroupsNamesForMember() when calling it with "User 1" as input, is to return "Group A" only. Because, only "Group A" has actually a member called "User 1". We might want to keep this behaviour, because we may need to have only the declared members of that group. But we can modify this method to also returns the members of the subgroups, by changing XwikiGroupService#getAllGroupsNamesForMember(), which returns the groups of a member. Other solution, adding a new method: boolean isMemberInGroup(DocumentReference memberReference, DocumentReference groupReference) which only check if the user (or the group) given on the input is a member of the group or not. But it's an API breakage. So my proposal is: 1/ Changing the behaviour of XWikiGroupService#getAllGroupsNamesForMember(), XWikiGroupService#getAllGroupsReferencesForMember(), XWikiGroupService#getAllMembersNamesForGroup(), XWikiGroupService#getAllMatchedMembersNamesForGroup(), XWikiGroupService#countAllGroupsNamesForMember() and XWikiGroupService#countAllMembersNamesForGroup() or 2/ Adding isMemberInGroup(DocumentReference memberReference, DocumentReference groupReference, XWikiContext context) in XWikiGroupService, which is an API breakage, and my Pull Request : https://github.com/xwiki/xwiki-platform/pull/117/ or 3/ Only change XWikiUser#isUserInGroup() and do the recursive stuff there. Thanks for your help! Louis-Marie