Placing Blocks/Hitting Fences

Put the summary of the bug you're having here

I was standing on top of a fence and I was trying to eat a piece of steak, I noticed that when I right-clicked to eat the steak my player just started hitting the fence as if I were left-clicking it, however I wasn't breaking the block. I did some testing and found out that from what I can see all non-placeable items do this when right-clicking on a fence.

Steps to Reproduce:
1. Be in a Minecraft Survival world in the 1.6 pre-release.
2. Look at a fence with a non-placeable item in your hand.
3. Right-click and you should see it happening.