What I expected to happen was...:
When I clicked the name box in the anvil GUI, the cursor would appear and I would be able to rename the item.

What actually happened was...:
No cursor appeared, and I was not able to edit the name of the item.

Steps to Reproduce:
1. Open an anvil.

2. Place an item in the first slot of the anvil.

3. Click on the name box in the anvil.