I tried to use the new preferences dialog widgets for my xulrunner application, and it's failing miserably, because it doesn't fall back nicely for missing preferences. Or maybe these prefs should move from http://lxr.mozilla.org/seamonkey/source/browser/app/profile/firefox.js#376 http://lxr.mozilla.org/seamonkey/source/mail/app/profile/all-thunderbird.js#165 into something like all-toolkit.js. Or the code in preferences.xml should check for it's platform itself. browser.preferences.instantApply and browser.preferences.animateFadeIn are the prefs.
*** This bug has been marked as a duplicate of 350528 ***