for whatever reason "setSelection" doesn't work for me (it sets the background grey, but doesn't set the checkbox to checked).  It also fails (for me) to preserve the selection when I go back to my original page. I ended up using something like this:

    onPaging: function() {
        save_grid_selection = $("#grid_table").getGridParam('selarrrow');  
    },
    gridComplete: function() {
        var gps = $("#grid_table").getGridParam();
        gps['selarrrow'] = save_grid_selection;
        for (var i=0; i < save_grid_selection.length; i++) {
            var $row = $('#'+save_grid_selection[i]);
            if ($row) {
                $row.find('.cbox').attr("checked",true);
                $row.attr('aria-selected',true);
                $row.addClass('ui-state-highlight');
            }
        }
    },

Use onPaging event to store the selected rows in other variable array and the gridComplete event to select the previous if the array is not empty. Use setSelection for this purpose.

Regards

Tony

so is there a easy way to keep the selected rows with the built in functions or anyone has a way to do it?