I'm done. I won't need the video any more. Again thank you. The video idea was brilliant. When users of my extensions have difficulties, I'm going to suggest that they make a video for me. I can follow the exact steps needed to observe and repeat the problem.
As far as this issue is concerned. It was a momentary lack of logical thinking on my part. The warning message is simply inappropriate. As near as I can tell, the functionality is correct: the item is moved to the new group and if the library is not the NPC library, the items (and group) are not shared.
In other words I put a warning message that is not needed into my code. You can simply ignore the warning message. If that is irksome to you. I have attached v0.0.11 to this post, an interim release or patch, as it were. Releasing this as mainline (in post one of this thread) and having everyone update, seems over the top to me. I'll add a caveat/know issue to post five of the thread, with a mention of this fix.
As far as the other problem is concerned, I could not repeat the issue. If you see it again, please let me know.