bug: zsh incompatibility

[in...@leon.vankammen.eu]

reproduce:

- Nathan: when I run less in the 80x24 that the 'less' command remains
visible on the top of the screen.  That doesn't happen in the actual
terminal when I'm
running the commands.  The find output is the first line in that
case.  The 80x25 recording behaves as expected and seems to be the
number of lines being
displayed.

- Nathan: Another issue that I encountered is that all my sessions
with zsh are unusable.  For some reason the previous lines text are
erased when the enter key is pressed.
 Output from 'ls' or any other command also gets erased in a similar
fashion.  I've attached a sample ttyrecord for you to experiment with
also.  It would really
be a shame if I can't post ttyrecords created with zsh - it's such a
cool shell.