Library /sys$common/syshlp/dbg$uihelp.hlb DEBUGUI, search_text  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Forward and backward search and replace operations can be performed by
  entering strings in the Find text and Replace with entry boxes and
  clicking on a directional arrow.

  If you continue to click on a directional arrow, or if you continue to
  press the Return key, a repeated search for the string occurs in the
  direction you indicate.

  You can also continue a search by choosing the Find/Replace Next or
  Find/Replace Previous items in the Edit menu.