Summary:
Items in inventories looses their colour when moved between slots to other slots.

What I expected:
Items remain their own colour all the time, including the time when they are moving between slots.

What actually happened:
Colour of items change to black and white when they are moving to other slots. The colour reappears after the items finished moving. This especially happens with items that are not blocks (eg torches, redstone, tools, armour, buckets, food, etc)

Steps to reproduce:
1. Put item(s) (eg diamond sword) in a random slot in your inventory.
2. Move the item(s) to another slot in the inventory