I am new to Kendo. This was happening to me for the chart. Other items like the date picker were working. I came across this note on another web site. I am surprised that this was not pointed out in the multiple threads posted about this issue anywhere at Telerik.
Solution for me: "You should include "kendo.all.min.js". The "kendo.web.min.js" doesn't include Kendo UI DataViz widgets."