The older version of Firefox ran Sumble Upon just great. Your newer version states "your version of Firefox does not support Sumble Upon". I use this function quite frequently and am very disappointed that it is not longer there. Even tried to go back to earlier version of Firefox but every time I try to download it, the download fails. Next move will be to discontinue using Firefox and go to Google Chrome of Chromium.....Hope you guys/gals will get on this bug right away as I am sure that there will be many others just as disappointed as I am. Thanks