@George_B are you sure about the onchange trigger not working with the sheet closed? I swear I’ve seen this work (at least I’ve never had an issue with it not working). I swear I’ve tested it and it worked, but it’s also not something I use much either. Not saying I’m right…just trying to verify if it’s still the case.
The attached post is just a reference to when I had tested it with the sheet closed, so I know I’ve done it recently.