Last use of an anvil causes player to drop their item

Upon using an anvil for the last time before it breaks, taking the output out causes the item to be dropped/thrown.

What I expected to happen was...:
I expected that the item would be placed into my inventory when the anvil breaks.

What actually happened was...:
I removed the new item (without shift-click) causing the anvil to break. As the menu forcefully closes, the item I was holding in the cursor is thrown onto the floor.

Steps to Reproduce:

1. Use all charges of the anvil.
2. On the last charge, pick up the new item with a click.
3. Anvil breaks, causing the menu to close.
   the item is thrown