Adding custom properties and other features to the Inspector is a great thing, but it seems that using the additionalNodes property when showing the debug layer / Inspector only works when at the same time you set embedMode to true:
We usually like to discuss bugs here before moving it to github (we use issues to track our work, and less for discussion). But as it does seem like it is a bug, it will be great if you submitted an issue on github. you can reference this forum discussion.
