Held Item Deleted when closing Inventory

This happened in SMP 1.7.5 and I thought I dropped the item and it de-spawned while I was afking. I was just in 14w21b and noticed something similar happen, not afking.

Steps, basically:

• I had an item selected (specifically, holding the item)
• I closed my inventory
• I expected the item to drop to the ground; instead it disappeared
• I repeated this about 3 times to the same conclusion

Again, this explains what happened in 1.7.5, but was tested in 14w21b as soon as I realized what was going on in 14w21b.

PS: I did a search to see if this bug has been reported, and I saw no matches to this (keywords: Item Deleted Inventory Closing)