LockSmith is an addon for rogues. It will show a lockpicking button if you have a lockbox in your inventory that you can unlock.

Keep clicking the button to unlock all boxes. The button will disappear when you have no more lockboxes that you can unlock.

Hold down the alt-key while dragging to move the button.

I recommend my CrowBar addon to open the boxes after unlocking them all.

Enjoy.

-Ammo