Not wishing to argue with the creator, but my Calibre library has always exhibited an order in the ID field.
I always enter the ID's in alphabetical order, ISBN; Amazon; GoodReads; Google; SmashWords, yet after saving the book, they display in the order:
SmashWords
GoodReads
Google
Amazon
ISBN
(basically backwards)
It annoys the stuff out of me, as I'm expecting the Amazon link to appear at the top of the list, but it's always near the bottom.