freebsd stable - Jun 2012 - Possible r237738 libedit regression with xfce4 and other terminal programs

Some update between r237683 and r237740 has caused a regression with
xfce4's Terminal program:
An attempt to resize a window by dragging a corner results in the
window immediately closing.
I have reproduced this on a Pentium 4 machine with an old ati radeon
9000 era card and on newer
machines with radeon 4xxxx cards.  There is one exception I have
noted: a Terminal window with
the results of
svn log | less
can be resized without closing.

While I have not exactly bisected the problem to r237738,
this regression is similar to one I have reported for DragonFly BSD
after a bisection to an update to libedit.
The identical symptoms lead me to believe the problem will be
manifested beyond xfce4's Terminal
and beyond the radeon cards tested.