Issue with Notehead set editor, can't delete and other question

Thanks!! I just have created it randomly to exemplificate the issue, because it happens in several projects.

I have recreated something similar, and created a new notehead set in the attached document. Now I can delete the clusterMiddleBlack headnote, but not noteheadBlack or half-diamond like in the screenshots… I wonder what it depends on…

clusters_proves.dorico (2.8 MB)

Thanks for attaching your project. I’ve started looking into this, but will need a bit more time, and will hopefully make some more progress later today. It looks as if Dorico is considering whether the notehead set containing the notehead is in use when determining whether the notehead can be removed from the set, rather than considering whether the individual notehead type is actually used – but I need to take a deeper look at how Dorico is building up its knowledge of which notehead sets and types are in use to be sure.

Thank you very much @dspreadbury!

Let us know if you find anything else, please.