Find out what properties change since last input?

This may not be much help, but when things start happening in an application which are not obvious (like this), the fastest way to figure it out is often ....... just ask the dev team!

If they are on hand of course. And helpful!

I've run into a few weird and wonderful non-standard ways of doing things and, a couple of them, I would NEVER have figured out if I hadn't been able to ask the guys that write and maintain the thing.

I like tristaanogre's idea though. I may give that a shot sometime. (Although, in at least one case, even that wouldn't have solved it. It might have told me what had changed, but I would still never have figured it out without the devs! It was a partially propagating tree list in case you're wondering. Checks part way down a list would trigger automatic checks on child nodes in some cases, and parent nodes in others. And they all used different shading to indicate their status. None of this used the "checked" status at all!)

Thank you Robert.

I will give it a shot!