Hi Ludwig,

Thank you for the logged feature request.

In general, the DateTimePicker still doesn't support RTL mode. However the implementation of that functionality is in our development plans. Indeed, we will take into consideration the request to change the positions of the "Set" and "Cancel" buttons when developing the RTL functionality, so that this behavior is available out-of-the-box when using RTL. But we won't proceed with providing a dedicated feature that allows to change the buttons positions. What could be done is to use some custom CSS in order to change their order:

    .k-button.k-time-cancel{
      order: 1;
    }

Here is a demo demonstrating that approach:

https://stackblitz.com/edit/angular-6u6zvk?file=app/app.component.ts 

Thank you for the provided feedback once again.

Regards,
Svetlin
Progress Telerik