Library /sys$common/syshlp/dbg$help.hlb DEBUG, Built in Symbols, %DECWINDOWS  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Enables you to determine whether you are using the debugger's
    command interface or Compaq DECwindows Motif for OpenVMS user
    interface. With the Compaq DECwindows Motif for OpenVMS user
    interface, the value of %DECWINDOWS is 1 (TRUE). With the command
    interface, the value is 0 (FALSE). For example:

    DBG> EVALUATE %DECWINDOWS
    0

    The following example shows how to use %DECWINDOWS in a debugger
    initialization file to position the debugger source window, SRC,
    at debugger startup:

    IF %DECWINDOWS THEN
       ! DECwindows Motif (workstation) syntax:
       (DISPLAY SRC AT (100,300,100,700))
    ELSE
       ! Screen-mode (terminal) syntax:
       (DISPLAY SRC AT (AT H1))