It's rare enough that you see a district court deny approval of a class action settlement. It's even rarer when the parties attempt to appeal the denial. All of this nonetheless transpires here.
For what it's worth, I agree with the per curiam opinion here. The disapproval of a proposed settlement like the one here isn't immediately appealable. The only thing I'd add to the opinion is that the rule here is similar to the rule that you can't appeal the grant of a new trial. The denial orders a "new settlement," which may well be better than the old one -- just like the new trial might be better than the one that was vacated. You have to wait and see, and don't get to appeal in the meantime. Even though that results in some hassle and expense in the trial court. That's just the way it works.
