X11 shutdown (logout from XFCE) errors

[jb]

Hi,

$ uname -a
FreeBSD localhost.localdomain 9.1-RC1 FreeBSD 9.1-RC1 #0: Tue Aug 14 03:56:40
UTC 2012     root at obrian.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  i386

I filed a PR# 171078
http://www.freebsd.org/cgi/query-pr.cgi?pr=171078&cat=

I worked with FreeBSD XFCE maintainer, we tried various XFCE options to see
if it is related to XFCE and we could not get rid of these errors.
I see similar reports on various lists but no conclusive answers.
We checked Xorg.log but could not see any obvious error.
I changed Intel to Vesa driver in xorg.conf but it did not help.

Do you have any suggestions what to look for/test to dubug it ?
jb