The Kendo UI widgets and the MVC extensions do not support multiple themes used on the same page. The problem is caused by the fact that both legacy MVC CSS files and current Kendo UI CSS files are registered on the page. I suppose you would want to remove the two Kendo CSS files.
Eventhough the different state colors in the legacy themes are correct, the MVC wrappers for Kendo UI may not look absolutely identical to the MVC extensions due to differences in HTML markup and behavior. This is the case with the dropdown's selected state, which is now actually a focused state. If you need to make it identical to the MVC ComboBox, please use
#3e94b4 is the selected state background color. Add the above CSS rule after registering the legacy WebBlue theme.
the Telerik team
Join us on our journey to create the world's most complete HTML 5 UI Framework - download Kendo UI