In my OSX Mavericks, two finger zoom in/out gesture isn't working on my Nightly version 29.0a1 My Environment: System Version: OS X 10.9.1 (13B42) Kernel Version: Darwin 13.0.0 Boot Volume: Macintosh HD Boot Mode: Normal Secure Virtual Memory: Enabled +++ This bug was initially created as a clone of Bug #788692 +++ User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:15.0) Gecko/20100101 Firefox/15.0 Build ID: 20120824154833 Steps to reproduce: I tried the 2-finger gestures on my Mac Touchpad to zoom in and out of a Firefox 15.0 page, using these Multi-Touch gestures that began with Mac OS 10.7. I find these two gestures extremely useful for enlarging certain Web pages. Bug 465257 submitted this bug for Thunderbird, but it apparently affects other Mozilla products as well. Actual results: Nothing. No zooming occurred. Expected results: A 2-finger spread should zoom in and a 2-finger pinch should zoom out in a smooth, continuous movement until the limits are reached.