jQuery Grid Plugin - jqGrid

I've got a grid populated with an initial sort order that is not one of the columns, but I need to let the user sort the columns.  Another event (outside the grid) reloads the grid as follows:

    jq132("#mylist").jqGrid('setGridParam',
        {
           datatype: "json",
            url: getListUrl(),
            page:1,
            sortname: "",
            sortorder: ""
        }).trigger("reloadGrid");

This works, In that the data is reloaded properly, but if the user has already changed the sort (clicking on a column header) the sort icon is left on that column.  I've tried:

  $("#gbox_mylist .s-ico").css('display', 'none');

to clear the icon, and that works, but if you click on the same column after the reload, the icon will not reappear.  You have to click on some other column, and then it seems to right itself.

Is there some way to clear the sort column entirely, as if the user had never clicked on a column?