FIX. RadDateTimePicker. When using custom format and the value is deleted, it is unable to set the time to 12:00 AM
When:
RadDateTimePicker1.Format = DateTimePickerFormat.Custom
RadDateTimePicker1.CustomFormat = "hh:mm tt"
and you delete the value (with delete key), then you can not set the time back to 12:00 AM by using arrow keys.