Based on the provided information and screenshot I conducted a few tests and it appears that the DropDownList widget's scrolling works as expected. Actually, you have stated that a Kendo UI ListBox is used, however, the provided code snippet and a screenshot are for a DropDownList. Which of the widgets is in use?
I have investigated the screenshot and I assume that the widget is not nested within another widget, am I correct?
In order for me to provide suggestions on how to deal with the faulty behavior, I would need a sample in which the issue can be replicated. Moreover, it would be very helpful if you provide additional details concerning the set-up you have on your side. For example, screenshots of the whole page, the widgets of use and code snippets.
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