Didn't try it again, but I did this:
1) have an item in hands, and one in inventory to do some action with and no space for the item in hands to store it to.
2) click some action on the item in inventory, so it gets replaced by the item you have in your hands
3) just after click press go forward (sprint), before the action animation (e.g. drinking) kicks in
4) item in hands in the first place should be on the ground (but it wasn't)