|When you have many users it is very difficult to select user in "Manage existing users shares" mode.|
It is necessary to SORT users by user (name), role and other fields.
Admin can see in field "user" (name) - first name + last name OR screen name (when defined).
User can change him names and how admin (other manager) can recognize that user after incorrect values?
I offer to allow an only administrator to change names of all users.