Is there a reason why you use such an old Fx (and TMP) version? As far as i know, 3.6.28 is the last update. Fx is now at 11.
Because the browser works fine. I don't have any concerns with it being too slow. It allows me to effectively browse webpages. Why do I need to waste my time continuously updating FF, worrying about extensions not working and losing functionality like the status bar and more because FF engineers are trying to justify their existence by continuously tweaking FF code? When something works fine, leave it alone!