Will definitely work with comboboxes. The reason I’ve been trying to avoid using them is because if you end up with several comboboxes, the user will have to click double the amount of times to change them, which I suspect may change/worsen the user experience (if that makes sense?). Obviously, for a big list of items a combobox is better suited, but a 3-state button I think definitely is nice and feels encouraging to click.
“optionbutton” is nice yeah!