This issue is caused, because the end-user selects an item on "touchend" event. The popup is closed when the click event is raised and that is why the element under the popup is clicked. You can overcome this issue with disabling the elements under the popup or with adding an overlay under the popup.
All the best,
the Telerik team
Join us on our journey to create the world's most complete HTML 5 UI Framework - download Kendo UI