When trying to quickly clear my inventory the items keep coming back if I go into a chest. Really annoying if you're trying to move items from a chest but your inventory is full in creative.
It doesn't just happen to the hotbar when pressing Q, it happens to the inventory too and sometimes leaves blank spaces in the hotbar that still place blocks when you right click.

To reproduce...
Go into creative,
Fill up inventory,
Fill up chest,
Now try to clear inventory and take contents from chest.

Not very fun is it...