After release of Firefox 4 Beta 7, Mac users are finding hard to to bring top of page with 3-finger swipe upwards, however Mac users can bring this old behavior by installing Swipe Top add-on. Another similar add-on Swipe Tabs allows to swipe right to switch to the next tab and swipe left to switch to the previous tab.
Both Swipe Top and Swipe Tabs are restratless add-ons, you can get the original panorama and navigation behavior by holding the “command” key while swiping.
You can also disable and uninstall Swipe Top and Swipe Tabs to get panorama original behavior.