使用ui-grid，当其他排序被删除时如何恢复默认排序

I'm using UI-Grid 3.0 (https://ui-grid.info/). I’d like to indicate to the user that there is a default sort applied to the data, but hide that default sort while the user is sorting by some other column. If they remove their custom sort, I want to resume the default sort. But I only want one column to be sorted-by at any time, to keep the UI simple for our users.).