With the new feature added in 20w46a, you can scroll button like the difficulty or the auto-jump, but you cannot scroll when a scrollbar is present (in the video settings for example).
I think the best approach is that you scroll normally, through the page unless you cursor is on a button, in this case you'll scroll through its different options.
Also, it doesn't make sense to me that you can scroll buttons but no sliders.
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