When you fall on a block in creative mode, particles are supposed to appear, but when you sneak on a block and go to farthest to a side without falling (there should be no block attached) and you fly up and fall, the particles do not display.

To reproduce:

1. Stand on a block (preferably with no blocks directly to each side).
2. Sneak and move the farthest you can to a side of the block-the side you move towards must not have an adjacent block! So, move in one direction until you can't sneak farther.
3. Let go of the sneak button, and fly up (don't fall or move).
4. Stop flying and let the player fall on the side of the block.
5. Look at the ground - no particles appear when you fall.