Items of different data values stack when pulling from the creative inventory

Expected Behavior:
Items of different data values do not stack from the creative inventory

Actual Behavior:
Picking up an item and then clicking on the same item but of a different data value will add to the stack

Steps to reproduce:
1. Take any item (i.e. spawn egg)
2. Open the creative inventory
3. Pick up the item and click in the creative inventory on a different data value of the same item
4. The stack in your hand is added to rather than dropped, ignoring the data value clicked on

Items known to produce the glitch:

• Spawn Eggs

• Tipped Arrows