I have a problem where if I add a datepicker to a dialog the datepicker always appears behind the dialog.
See here for an example:
https://plnkr.co/edit/XIAgXksJLimneb3NDXAg?p=preview
I basically took the following example from your portal and added a datepicker
https://www.telerik.com/kendo-react-ui/components/grid/editing/editing-external-form/