Different fireworks made with shift+click

When crafting firework rocketss and firework stars, if you have different sized stacks in the crafting window, shift+clicking to craft all of the item will craft multiple types of firework rockets or firework stars.

Examples:

• Rockets:
  2 gunpowder + 1 gunpowder + 2 paper
  Mousing over the result says "Flight Duration: 2".  Shift+click will craft 3 of those and also 3 with "Flight Duration: 1".
• Stars:
  2 gunpowder + 2 cyan dye + 1 wither skeleton skull
  Mousing over the result says "Creeper-shaped". Shift+click will craft 1 of those and also 1 with "Small Ball".

I noticed this result first in a multiplayer survival world at a crafting table.  I then went into a creative single-player world and tested at a crafting table, changed to survival, and tested in the inventory.  This happened each time I tested.