Hi Magda,
I would kindly ask you to open your inquiry using account with an active license in order the benefit from Telerik support service and target the appropriate forum channel.
The RadDateTimePicker control is offered in a few suites (e.g. WPF, WinForms, ASP.NET) so considering the one you are using please require assistance in the right
forum thread.
Thank you.
Regards,
Zdravko
Telerik