Comment 11 for bug 596862

I think the users should always be able to "undo". Users as human, so by definition they make mistakes.

There are complex cases that should be un-done by hand on several steps (i.e. you shouldn't be able to simply cancel an invoice that has been paid), but we should make sure that this use cases are covered and can be worked around (i.e. you can unreconcile a paid invoice and then cancel it).

So, if a user makes a mistake and confirms a picking that shouldn't have been confirmed, he should be able to 'go back' either canceling the picking (if no workflow is affected) or (if confirming the picking affected other document's, like an invoice, workflows) making an inverse/return/refund movement.