Library /sys$common/syshlp/decw$helphelp.hlb Overview, Over guide functions, buttons_exit  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  There are two buttons in the Help window, labeled Exit
  and Go Back.

  Selecting the Exit button closes the Help window
  and returns control to the application you were
  running when you asked for help.

  For information on other Help features, make an
  appropriate selection from the list of additional
  topics. Select one of the menus to look at some
  advanced help features.