Setting the Western Sans-Serif font affects the font used in the pull-down menus and buttons of the Preferences dialog. That opens the possibility of a user mistakenly setting the font to a non-Latin-characters one and thus making the Preferences dialog's controls impossible to understand next time.
dup. *** This bug has been marked as a duplicate of 56197 ***
mass verification of duplicate bugs: to find all bugspam pertaining to this, set your search string to "DuplicateBugsBelongInZahadum". if you think this particular bug is *not* a duplicate, please provide a compelling reason, as well as check a recent *trunk* build (on the appropriate platform[s]), before reopening.