Don’t know if this is just me here…
Made a test toolbar in default and now I want to delete it. Delete button doesn’t work. Edit button doesn’t either. Add, Properties and Close do work.
The add, edit and delete buttons were intended for the actual buttons on the toolbar, but I can see where this could be useful when the toolbar doesn’t have any buttons at all. I’ll try to get that button hooked up in a way that works for this case. (https://mcneel.myjetbrains.com/youtrack/issue/RH-79369/Delete-Toolbar-when-no-buttons-exist)
As a side note, you should be able to edit->delete that “Test” toolbar from the menu at the top of the page.
RH-79369 is fixed in Rhino 8 Service Release 4 Release Candidate