The VBTKitEnv interface provides a way to collect in one
   place the various environment variables that widgets in the
   vbtkit use for controlling their appearance. 
INTERFACEVBTKitEnv ;
SCROLLBARLOC specifies where scrollbars should be placed.  The
   possible values are north, northeast, northwest, south,
   southeast, southwest, east, and west.  The default location for
   a vertical scrollbar is west; and for a horizontal scrollbar, the
   default location is south. 
VAR (* read-only after initialization *) ScrollbarWest: BOOLEAN := TRUE; ScrollbarSouth: BOOLEAN := TRUE;
TEXTPORTMODEL specifies the editing model that text-editing widgets
   should use.  The possible values are emacs, ivy, mac, and xterm;
   emacs is the default value.  See the TextPort interface for more
   information. 
VAR (* read-only after initialization *) TextPortModel: TEXT := "emacs"; END VBTKitEnv.