I guess you triger the window by trying to right click on one of the contacts and then highlighting "Messenger Plus! features" which shows an extra item called "Open"
Popup ListBox - by 7d5 on 10-30-2008 at 09:02 PM RE: Popup ListBox - by Matti on 10-31-2008 at 09:17 AM RE: Popup ListBox - by 7d5 on 10-31-2008 at 10:32 PM RE: Popup ListBox - by Matti on 11-01-2008 at 08:00 AM RE: Popup ListBox - by SmokingCookie on 11-01-2008 at 02:16 PM RE: Popup ListBox - by 7d5 on 11-07-2008 at 10:45 PM