Windows 7 Home Premium 64-bit (6.1, Build 7601)
Java 7 Update 55 (64-bit)
Closing sounds plays when you close your inventory.
Steps to reproduce:
1: Open a chest
2: Close chest & quickly open your inventory (Before chest visibly closes)
3: Also close your inventory shortly after (Within around half a second)
4: Closing sounds can be heard when the chest & your inventory is closed