the icon used in object group list for samba user come from the system plugin

Hello,

when only using the core plugins + samba for user management the icon for samba doesnt appaers because it comes from

it should be added as select_winuser.png to make it work even without the systems plugins

Cheers

(from redmine: issue id 1684, created on 2012-12-10, closed on 2012-12-11)