If you place an anvil on a block with a button, the anvil replaces the button.

I went to go press a button to test out something I was working on and I had an anvil in my hand and I missed the button. When I hit the block with the button on it it placed the anvil and got rid of the button. If you actually press the button this does not happen.

Steps to Reproduce:
1. Place button on any block
2. Have anvil in hand
3. Right click on block with button.