I created a user : user_demo1, gave him maximum right all every module and every technical rights. As a result, he belongs to the group : "Administration Access right" and "Administration / Setting".

But I can't modify anything in the General Setting menu. Following message is displayed :

Access Denied The requested operation cannot be completed due to security restrictions. Please contact your system administrator. (Document type: Partner, Operation: read)

More over, is it normal that user_demo1 can't see the administrator user in any group ?