+2  A: 

I believe that this is a bug related with missing line-height CSS style, which is already fixed. More information about the problem in this forum thread: http://www.telerik.com/community/forums/aspnet-mvc/datepicker/error-on-page-when-selecting-month.aspx

George K
Yes got the SP1 ( had to get the commercial license but I think it is worth it). Thanks for putting such a good product together.
GlobalCompe