Default Group for New Workarea?

BBeaver

When I created a new workarea yesterday and chose Group sharing, the group name field filled with a Windows SID by default. Even when I deleted this SID and entered a local group name, both the local group and SID were added to the permissions on the Workarea. Does anyone know where this default SID is coming from? We are on TS 6.1 - W2K server. It's been a while since we have needed to create a new Workarea, but I don't remember a default group ever being filled in before. Thanks for your help!