BB often rewrites .blackboxrc on exit

[David W. Talmage]

I've read here that BlackBox rewrites .blackboxrc on exit if you changed the 
Blackbox settings during your session.  On my workstation, BB rewrites 
.blackboxrc on exit even when I don't make changes.  The only component of 
.blackboxrc that changes is session.menuFile.  BB resets it to the system menu 
instead of the one I have in my .blackbox directory.  BB doesn't do this every 
session.  I haven't yet found a pattern for this behavior.

I'm running XFree86 4.0.1, BB 0.61.0, and bbkeys 0.3.3 on a Linux 2.4.0-test9 
kernel.  My home directory is in an AFS volume, not a local one.