Thanks for your feedback.
It appears that there this is an issue with Calendar - it is generating an additional empty CalendarButton and this is why you have more buttons in the collection. I have logged that in our internal backlog and it will be considered for fixing in one of the future release versions of the controls. Meanwhile what I can suggest you would be to also check if the content.Text is not null in order to get the correct buttons:
var calendarButtons =
.Cal.ChildrenOfType<CalendarButton>().Select(bt => bt.DataContext).OfType<CalendarButtonContent>().Where(content => content.ButtonType == CalendarButtonType.Date || (content.ButtonType == CalendarButtonType.TodayDate && content.Text !=
Hope this helps. I have also updated your Telerik points for your involvement.
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