Thanks, I figured that it might be a bug and have submitted a report via FeedbackAssistant (#FB9079551) and raised a DTI where they told me you had responded here :-) Yes I have existing application with existing archives. Note that the attachments are PDF documents or images the user may have pasted in to the text view. Not sure whether it would be possible to convert the file attachments to data without loosing some file details but I suspect so. Anyway thanks for the great response. I don't think I have ever had a useful response from anyone from Apple on these forums before - great to see such good support these days. ***** (that's 5 stars!) Regards

This might have nothing to do with your issue but we experienced the same problem with our background reporting threads where they suddenly took forever to run. We solved that by setting the thread or queue priority to be user interactive (or something like that). Sorry I don't have the details in front of me. I have no idea if you can do the same with the drawing threads for CATiledLayer - or whether this the issue but thought it was worth mentioning. Let us know if you find the solution.

Yes me too - I have logged this as a bug with Apple.

OK well I solved this after much searching - it's a long story that involves using CAMetalLayer and the correct CIFilter pipeline as well as coordination with view resizing or scrolling but the end results is a realtime view of the effects of changing parameters on CIFilters. Basically a recreation of Photo's and Lightroom functionality with ability to view thousands of thumbnails, smooth scrolling and RAW editing. It can be done ... and it seems I can't include a URL to the result in this post!

You can't use Realm Collections with SwiftUI (or other reactive languages). The basic issue is because when you delete the realm object the object is marked as invalid and any attempt to access it's properties throws an exception - pretty brutal huh !! No quiet - sorry this is not allowed ! The way SwiftUI works is is keeps track of the list of items and when the list changes it gets notified that something changes and then it diffs the new list with the old list and neatly adds or removes items as required. Herein lies the problem - it still has a reference to the now deleted object in realm and attempts to access its properties causing an exception - OR - in your case it is checking the OLD list, which is actually a live updating REALM collection, which already has the item removed - and hence the index out of bounds error. Check out the new frozen() option and the same in the 5.2.0 SwiftRealm release - not sure if that completely fixes the issue, but lets hope so !

Nevermind preserving between launches - what about preserving state when switching between views - simple things like a list view forgets what item was selected and what its scroll position was.

Thanks, I'll try that - however I suspect the device is not USB UVC compliant. It's a Nikon Z6 and I guess it will need a vendor specific driver much like the recently announced Cannon USB webcam utility. Nevertheless I'll run IORegistryExplorer as suggested above. There is some third-party software that seems to work with the specific Z6 camera - how is it they are able to access the video stream from the camera via USB without using a vendor specific driver ? Is there some other way to access the device directly from within an application ? Regards