Ah thank you Quinn! I wasn't aware of that restriction on non-resource functionality.

I'll see how much I can get away with using messaging before looking into shared memory. Thanks for the advice Quinn™ :-)

No worries. I was just pointing out that feedback from Apple on here isn't quite rare.

Thanks very much for your feedback! I didn't realise you could include helpers in Mac App Store apps. I'm going to check your app out :-)