Either, depending on the item.
Right now I've had an order stuck for a week or so because I think one item has to be shipped from a store and the other from a warehouse, so they need to get them together first. (Should have ordered each separately, but stock was running low on one so I immediately jumped on it.)
That's interesting, especially as it seems I am encountering the opposite problem as you, with one item being shipped and the other still in limbo. Weird also because the charge in paypal is still showing as pending but some came out for the 1 item that shipped. I've actually never seen that happen before. Thank you for the help as well, I appreciate it.