Comment 15 for bug 1081015

lockPref is not valid syntax outside of mozilla.cfg in either the Mozilla version of Thunderbird or the Ubuntu one. Using it in any preference file will make the entire file invalid. It only works in Debian's Icedove due to this patch - http://patch-tracker.debian.org/patch/series/view/icedove/24.0~b3-2/fixes/Allow-.js-preference-files-to-set-locked-prefs-with-.patch