Add someone to the list of members without inviting him or her. It should generally be reserved for emergencies, because the person will NOT be invited to be a member of the share group and will only be a recipient.

Sends the entire contents of the shared folder to the selected share group member.

Deletes someone from your list of members for the share group selected to the left.  Generally you should only use this to remove an invalid member, but this could also be used to avoid sending messages to someone.

Invites someone to join the share group selected to the left. Option-click to do an advanced add where you can add someone to your list without sending him or her an invitation.

Displays the list of share group members for the share group selected to the left.