When dropping a stack of items that are in your hotbar while being in the creative mode inventory, the stack of items is deleted from existence.

Steps to reproduce:

1. Open the Inventory in creative mode
2. Take a stack of items and place them in the hotbar
3. Drop the whole stack at once (Ctrl + "Drop Selected Item" key, usually bound to Q)

Observed result:
The stack of items is deleted from existence.

Expected result:
The stack of items drops from your hotbar properly.