RMAIL display problem

[Ken Harrenstien <KLH@MIT-MC.ARPA>]

I'm not sure where the fault for this one might be, hence the shotgun
message.

In RMAIL, when using "space" to step through successive screenfuls
of a long message, sometimes output fails to stop at the mode line;
it continues for several more lines and runs right off the bottom of
the screen, causing the terminal to either scroll or wrap up to
the top (depending on one's terminal).  The screen is then permanently
messed up until a complete redisplay is forced with ^L.

This happens for me when connected to MC either via SUPDUP (ie as a
software TTY) or via TELNET with a :TCTYP DM2500 declaration.  At
first I thought it might be a CRTSTY/SUPDUP problem, but my TELNET
experiments have convinced me that it really is MC's fault.
However, I haven't been able to find a foolproof way of reproducing
the lossage.  All I can say is that in the course of reading through
several SF-LOVERS digests on a 24x79 screen, this bug almost always
crops up someplace, sometimes twice or thrice in a row.  I type:
	N E ^K ^X r				; to invoke RMAIL
	<spaces as needed to read msg> d	; for each message

This is probably a TECO bug of some variety, but there's an off
chance it might be an ITS TTY handling bug.  It's even possible
that some EMACS code is screwing up the redisplay.  This has happened
for quite a while (several months).  I hope someone else has a
notion of what to look for at this point.  If necessary, I could
try again to save a reproducible instance of this, although it is
a rather painful task.