Library /sys$common/syshlp/dbg$help.hlb DEBUG, DISPLAY, Qualifiers, /DYNAMIC  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /DYNAMIC (default)
       /NODYNAMIC

    Controls whether a display automatically adjusts its window
    dimensions proportionally when the screen height or width is
    changed by a SET TERMINAL command. By default (/DYNAMIC), all
    user-defined and predefined displays adjust their dimensions
    automatically.