Put the summary of the bug you're having here

What I expected to happen was...:
I didn't think anything should of happened its just a small thing that effects the game very largely and needs to be fixed.

What actually happened was...:
You can rename or add enchants or repair items using the anvil without using any exp.

Steps to Reproduce:
1. Get an item
2. Put it inside the anvil on multiplayer/singleplayer survival/creative
3. Rename it, add a enchanting book or repair it but dont actualy take the item out of the right hand side
4. Hover over the item in the right hand side and click the drop button and it will use no exp and drop it out the anvil with your rename or enchant ect