the popupLayout.Closing fires multiple times during life cycle. And the I still haven't figured out how to use the ICommand interface you now require.
Why did this become so complicated? I would have expected implimenting this control would have taken 15 or 20 minutes. So far I have spent 3-4 hours on this control and it still is not functioning the way I need.
(Last updated on: June 24, 2019).