Firefox startup use of /tmp

I have a small question about how Firefox uses /tmp at startup.  I have 
been trying to figure out why Firefox would crash randomly, which is 
still ongoing.

However, I had created a script (/tmp/firefox) just to play a bit.  This 
actually caused a slowdown when starting a new instance (1s -> 6s).  It 
appears Firefox creates a temporary directory (${TMPDIR}/firefox).  The 
fact that it just exists confuses Firefox for awhile before it shows a 
window.  Any ideas about that or a way to make it create a unique 
directory for its startup to prevent future conflict that confuses 
others (or me, after I forget)?

Sean
-- 
scf@FreeBSD.org