We just would like to customize the open/close combo selector with two different icons.
Actually, there is no easy way to do that because there is no CSS selector that has two different values based on popupstatus.

The only way is to introduce a login on every combo as shown on link: https://stackblitz.com/edit/angular-2gdnhv?file=app/app.component.ts

we are just asking for a kendo native solition.