/**
 * @private
 * See {@link Ext.grid.feature.Grouping} for an example of how to add a summary row to 
 * a grouped grid
 */
Ext.define('Ext.grid.feature.GroupingSummary', {

    extend: 'Ext.grid.feature.Grouping',

    alias: 'feature.groupingsummary',

    showSummaryRow: true
});