M-Q in CONVERSE

[Eugene C. Ciccarelli <ECC at MIT-AI>]

In ZWEI in System 79.29, ZMail 40.7, Remote-File 2.0, LMFILE-Remote 5.3,
microcode 849, 60.45Hz, on Lisp Machine Four:

Filling a paragraph with Meta-Q (COM-FILL-PARAGRAPH) in CONVERSE
can destroy one of those heavy black lines.  Could they be
declared paragraph separators?  Also note that using M-X Undo to
undo the fill makes things look ok, but CONVERSE complains that
the buffer is broken nonetheless, and you need to M-X Regenerate
Buffer.  I am willing to believe that Undo is tempting fate,
since one is not supposed to be killing those lines, but at least
could be protect them from M-Q?