Here's a partially pub'd opinion that speaks straight to the soul of every appellate nerd! Check this out from the intro:
The bulk of this opinion is devoted to appealability, because it poses a more
difficult issue than do the merits.
With regard to the order awarding costs, there is a split of authority as to whether
such an order is appealable when it is made after a voluntary dismissal without prejudice.
We will follow the case law holding that it is appealable. The [Appellant], however,
failed to file a timely appeal from that order.
With regard to the order denying the motion to vacate, ordinarily such an order is
not appealable on grounds that could have been raised in an appeal from the underlying
order. This bar does not apply, however, when the underlying order is void. Moreover,
the appeal is timely with respect to this order.
The MetNews' coverage is here
Fourth District Says Post Dismissal Cost Orders Are Appealable.