Since the latest update from FF to 31, the nav buttons have been displaying as code and not using the font. It only happens in FF. The following article leads me to believe something was changed in 31's handling of unicode and that it probably needs to be looked at here. I'm not seeing the errors in console as described but the arrows are not appearing. I'm guessing it is somewhere in the library but am not a strong enough developer to sort it out. I have the latest version of the library - 2.2.2 installed.