I have a Macbook Pro, my track pad does not work with Firefox 4.0 and above, it does, however, work with Safari and Google Chrome. I googled it and this is what I found: Can no longer do "pinch open and close" on MacBook Pro trackpad Macs have a trackpad function where you can enlarge or reduce the size of the image in a window by using two fingers sweeping apart or together. (pinch open-close) With the installation of Firefox 4, I lost this functionality. I want it back. 21 people have this problem 4 new this week