I too have noticed Budgie can be fickle on what it will or will not allow you to pin to the panel. I do not know of a way to force it to pin something. :\

However, looking at the Budgie roadmap: https://github.com/solus-project/budgie-desktop/blob/master/TODO.md

I'm hoping the feature 'Add pinning capabilities to the Budgie Menu itself' will solve these issues. :)

Pinning on the Budgie menu wouldn't help

This thing has completely the wrong window class..

Thanks, the roadmap looks very promising. I will wait for updates and I think this issue can be closed.

I see, so there is something wrong with Anoise?