FIX. When we change the Culture property, the control will display the current date even if the value of the control is NULL

Workaround:
Set an empty string to the Hosted TextBox control after the Culture set.
For example:
radDateTimePicker1.Culture = Thread.CurrentThread.CurrentCulture;
radDateTimePicker1.DateTimePickerElement.TextBoxElement.TextBoxItem.HostedControl.Text = "";