What I expected to happen was...:
Using right click for bow or eating food etc will not work

What actually happened was...:
Doesn't do anything, although right clicking chests still seems to work.

Steps to Reproduce:
Not sure as It was working fine and had been playing 1.7.2 for a few days
without issue then randomly I was farming some dirt and finished up exited
my little hole to find a zombie waiting for me, went to shoot with my bow
and it wouldn't work and hasn't since.

Notes:
I can Still right click chests.
have completely re installed Minecraft, Issue still present.
have tried creating a new world, still doesn't work.
have checked system preferences and right click is still bound correctly.
have checked my minecraft options and right click still bound to button 2.

It would sound like something has changed in the computers settings instead of Minecraft since I have completely reinstalled but issue is still
there, however.

Since right click is still working for chests it's quite weird and it stopped working during the play session.