Accessing OS X built in dictionary lookup in Firefox I am really frustrated that Firefox does not provide the three-finger-tap lookup operation is in built in OS X. What is baffling me is that it supports other gestures such as two finger swipes and taps. So why not the 3 finger tap dictionary ? 

Is this possible to actually implement ? Or is it because access to in built dictionary and trackpad is blocked by OS ? How can I start looking at this problem ?
As of now (Dec 1 2014), although the option is not present in right-click menu, three-finger dictionary lookup works perfectly fine in my Firefox (Developer Edition 35)

Also there have been certain plugins which help you look up words in dictionary through right click. For example https://addons.mozilla.org/en-US/firefox/addon/look-up-in-dictionary-7261/

EDIT (Oct 2017): I'm now using the new e10s Firefox and the dictionary lookup still works. You don't need any plugin, just tap with three fingers or press Control + Cmd + D.