I uploaded another video to show you what it looks like since the recent changes:
https://youtu.be/U49T6jDiO4U
The bar addon is available on
GitHub.
I think it doesn't feel right in the way it's currently designed. The way the buttons pop in and out is a lot of change on screen for something that happens as frequently as a modifier change. It might actually be better to always keep them visible, but indicate in some other way which one in the cluster is focused.