Thank you for writing.
Yes this is the default behavior, the drop down is closed but the control is still focused. This is why you are still able to change the items with the wheel.
One way to solve this is to just disable the mouse wheel:
Another approach is to set this property when the popup is opened and then closed. This way wheel will work only if the drop down is opened:
sender, EventArgs e)
sender, Telerik.WinControls.UI.RadPopupClosedEventArgs args)
Please let me know if there is something else I can help you with.
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