There is a display issue when using the agenda view - if there are fewer than 4 events displayed then clicking on the date range in the header shows a calendar which is clipped at the bottom. Presumably this is due to it being constrained by the height of the events area. This occurs even though there is plenty of height available to the control. Please see the attached screenshot which is taken from your demo site:
http://demos.telerik.com/aspnet-ajax/scheduler/examples/overview/defaultcs.aspx