scrolling region behavior on vt100 terminals

[Tim Tsai]

  I'm having a little trouble figuring out vt100 emulation on several
communication programs I'm using, specifically with the set scrolling
region command.  What should be the proper behavior for a vt100 terminal
when the following are set for the scrolling region:

    from lines 20 to 23 (assuming that 0 is the first line)
               21 to 23
               22 to 23
               23 to 23

  On Procom Plus, setting 23/23 will scroll the whole screen.  Using
NCSA Telnet (with clarkson modifications) and CUTCP, setting any of
the above will scroll the last four lines.  Telix works as expected
using any of the above settings.  Which one is correct?
  Many thanks in advance..

-- 
  Never argue with a fool, people might not know the difference.
                                                       <Murphy's Law>