(Java Parity) Items in inventories

Items held with the mouse are the same size as items in a slot. The item count is displayed in white and the tip of the mouse cursor contacts the very center of the item

When dragging items into multiple slots, the slots are highlighted beneath the item texture. When the distribution is even, the empty remainder is not shown.

Highlighted slots show a transparent gray overlay above the item and slot.

When shift-clicking items, the item appears in the destination slot instantly.
https://gfycat.com/OrganicClosedEelelephant