An idea on the changing preferences problem. (I have had this problem as well) I have found with OS 10 generally ( I use 10.3.9 / VW 10.5.1 ), that apps (including the Finder) will reset their prefs back to their previous session setting if that app hangs during a session.
An idea that may be a work around until the problem is fixed is to set your prefs and then quit VW's. Reboot VW's and see if the prefs remain after general CAD-iing and undo-ing. Haven't tested this -but will do. All of those in this thread might test it and see if they have any joy.