I fully realize this may be one of these features that Apple has reserved for itself and not provided any third-party APIs for, but one of the nice new things about the iOS 9 Reminders app is that lock screen notifications are actually “sticky” across device unlocks. In other words, they will remain in place until the user takes some action on them – either dismissing them entirely, or completing or snoozing them.
When I’ve played with Reminders, I’ve actually found this to be a really handy feature, since of course with life on an iPhone on the go, it’s easily possible to see a reminder come up alongside something that’s slightly more pressing, unlock the iPhone to deal with the other thing (like an email or text message), and then basically forget about the reminder. With iOS 9 Reminders, it will still sit there on the lock screen, whereas with OmniFocus, it’s disappeared unless you go looking for it in Notification Center or open OmniFocus itself.
In fact, having those reminders stay on the lock screen helps them be actioned more quickly as well – I can take a quick glance, see I still have something there to do, and then cross it off right away without having to now go back into OmniFocus and find it again.
As I said, I wouldn’t be surprised at all if this is yet another case of Apple’s own special privileges, but if there’s any way for OmniFocus to do this I think it would be a nice option to have.