When checking a barrel for inventory, it occasionally will not show the inventory window, although I can scroll through the other barrel sections. Sometimes I can highlight the barrel at the top of the selection screen and press my right joystick to minimize the barrel options, and then press it again to open the options. This sometimes reveals the inventory, but sometimes it does not. I have found that selecting the inventory crate icon underneath the top barrel icon will minimize the inventory even if it isn't showing up, and pressing it again will reveal the inventory. I've tried this method and it has worked for the last few times.