Oh, duh, I saw the Pause menu before, but only looked at the activity list.
However, the pickup only works with the silver and gold box. I tried the bronze box first and there the pickup does not work, even after learning it when picking up one of the other two boxes.
Edit: Oh, I know just heard that guy wonder if I'm strong enough. Is the bronze box too heavy or something? I realize it's not top priority, but I would impede movement then, instead of not responding to the mouse click for pickup.