Bags and Merchants simply opens / closes all bags when you trade with a merchant, a player, the auction house, the mailbox, the bank and such.

You can get the latest version here. However, I suggest you get WinAceUpdater from www.wowace.com and download and update it with that program. It will be a great timesaver if you use more Ace mods in the future.

Tip: Bind "open all bags" to "b" and you’ll find yourself just hitting "b" instead of ever using the bag bar if you use this mod.