[Evolution] Eliminating "Group by threads"

[George Reeke <reeke mail rockefeller edu>]

Dear colleagues,
   I use evolution 2.32.3 as supplied with RedHat Linux 6.6
(and am not in a position to update).
Is there some way I can permanently turn off "Group by Threads"?
This seems to come on perhaps by default for new folders but in
any event I never want it.  I cannot find anything in Preferences
or in the gnome configuration editor that would allow me to turn
it off or at least make it not the default.  I will be happy to
edit interface source code files if that is what it would take.
   Thanks,
George Reeke, Ph.D.
Head, Laboratory of Biological Modelling
The Rockefeller University
1230 York Avenue
New York, NY  10065
email:  reeke rockefeller edu