Currently it is not possible to touch-scroll the locked section of the Grid on mobile devices - this is a known limitation:

https://www.telerik.com/kendo-angular-ui/components/grid/columns/locked/#toc-known-limitations

https://www.telerik.com/kendo-angular-ui-develop/components/treelist/columns/locked/#toc-known-limitations

Please provide the opportunity for touch-scrolling the locked section of Grid and TreeList similar to the one available on other devices via the mousewheel.