[MC-218712] Debug pie has purple box when moving an enchanted item

The bug

If your mouse is moving an enchanted item, the debug pie will have a weird purple box around it. It goes away if you have a potion effect, however.

Steps to reproduce

Open debug pie (Shift+F3)
Open your creative inventory.
Click on an enchanted book to move it around. (Don't click it into another inventory slot, though.) --> Notice the purple box around the debug pie.

Discovered while testing and related to ~~MC-218596~~.