In general, the scrollbars that are rendered are the ones provided by the browser itself. There is not any logic from the Kendo UI ListBox which modifies the behavior of the scrolling.
Nevertheless, I have conducted several tests with the latest version of the Kendo UI suite and, to me, it appears that that the scrolling works as expected. Can you replicate the faulty behavior in the project attached to my response and send it back to me?
Looking forward to your reply.
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