You could try changing the default rendering of otherMonthsDays
with the following code:
sender, Telerik.Web.UI.Calendar.DayRenderEventArgs e)
(e.Day.Date <= e.View.MonthStartDate || e.Day.Date >= e.View.MonthEndDate)
I hope this helps.
the Telerik team
Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items.