It works using a private osx api for using the macbook multitouch trackpad code and some middleclick code. Middleclick is really useful for all the Firefox junkie who loves to open in a new tab as it doesn’t require to use the keyboard (cmd+click is the default middleclick). MiddleClick should not interfere with the swipe gesture and you should not click the trackpad as it will send a click and middleclick at the same time!