You would need to set some value for the End property as if leave it blank ti will remain with its default value:
DateTime(1000, 1, 1, 1, 0, 0)
And this will lead to an incorrect Appointment and it will not get rendered (the End will be before the Start). So please set some date that is actually after the Start date (it could be an year later for example).
Hope this helps.
Telerik by Progress
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