It seems once user clicks a column to do sorting, there is not a way to disable sorting and rollback to original order, right?

At first, I want to add a menu "disable sorting" in column header menu and restore to original order. But after read the code, I notice that the store is sorted. And there is not a method to rollback store order either...

Does anyone have similar requirement? How to implement unsorting then?
Any suggestions and ideas are appreciated. Thanks