set a default pref to prevent the JS exception. r=sspitzer git-svn-id: svn://10.0.0.236/trunk@79411 18797224-902f-48f8-a5cc-f745e15eee43
set a default pref to prevent the JS exception. r=sspitzer git-svn-id: svn://10.0.0.236/trunk@79411 18797224-902f-48f8-a5cc-f745e15eee43