In Superflat Tunnelers Dream Creative mode, quick swaping items then placing duplicated them in creative.

What I expected to happen was...:
To place the item normally after quick swapping them

What actually happened was...:
Item that was quick swapped was duplicated

Steps to Reproduce:
1. Be in a world that is Super Flat, Tunnelers Dream Preset, Creative mode then create world.
2. Place TnT in slot 1
3. Place Redtone Torch in Slot 2
4. Open inventory
5. Move mouse over TnT in slot 1.
6. Press the number 2 key to quick swap.
7. Close out of inventory
8. Press number 2 key to select the TnT
9. Place TnT
10. Item gets duplicated