The source code

    Ext.onReady(function(){

        Ext.QuickTips.init();

        var xg = Ext.grid;

        var reader = new Ext.data.JsonReader({
            idProperty: 'taskId',
            fields: [
                {name: 'projectId', type: 'int'},
                {name: 'project', type: 'string'},
                {name: 'taskId', type: 'int'},
                {name: 'description', type: 'string'},
                {name: 'estimate', type: 'float'},
                {name: 'rate', type: 'float'},
                {name: 'cost', type: 'float'},
                {name: 'due', type: 'date', dateFormat:'m/d/Y'}
            ]

        });

        // define a custom summary function
        Ext.ux.grid.GroupSummary.Calculations['totalCost'] = function(v, record, field){
            return v + (record.data.estimate * record.data.rate);
        };

    	// utilize custom extension for Group Summary
        var summary = new Ext.ux.grid.GroupSummary();

        var grid = new xg.EditorGridPanel({
            ds: new Ext.data.GroupingStore({
                reader: reader,
    			// use local data
                data: app.grid.dummyData,
                sortInfo: {field: 'due', direction: 'ASC'},
                groupField: 'project'
            }),
            columns: [
                {
                    id: 'description',
                    header: 'Task',
                    width: 80,
                    sortable: true,
                    dataIndex: 'description',
                    summaryType: 'count',
                    hideable: false,
                    summaryRenderer: function(v, params, data){
                        return ((v === 0 || v > 1) ? '(' + v +' Tasks)' : '(1 Task)');
                    },
                    editor: new Ext.form.TextField({
                       allowBlank: false
                    })
                },{
                    header: 'Project',
                    width: 20,
                    sortable: true,
                    dataIndex: 'project'
                },{
                    header: 'Due Date',
                    width: 25,
                    sortable: true,
                    dataIndex: 'due',
                    summaryType: 'max',
                    renderer: Ext.util.Format.dateRenderer('m/d/Y'),
                    editor: new Ext.form.DateField({
                        format: 'm/d/Y'
                    })
                },{
                    header: 'Estimate',
                    width: 20,
                    sortable: true,
                    dataIndex: 'estimate',
                    summaryType: 'sum',
                    renderer : function(v){
                        return v +' hours';
                    },
                    editor: new Ext.form.NumberField({
                       allowBlank: false,
                       allowNegative: false,
                       style: 'text-align:left'
                    })
                },{
                    header: 'Rate',
                    width: 20,
                    sortable: true,
                    renderer: Ext.util.Format.usMoney,
                    dataIndex: 'rate',
                    summaryType: 'average',
                    editor: new Ext.form.NumberField({
                        allowBlank: false,
                        allowNegative: false,
                        style: 'text-align:left'
                    })
                },{
                    id: 'cost',
                    header: 'Cost',
                    width: 20,
                    sortable: false,
                    groupable: false,
                    renderer: function(v, params, record){
                        return Ext.util.Format.usMoney(record.data.estimate * record.data.rate);
                    },
                    dataIndex: 'cost',
                    summaryType: 'totalCost',
                    summaryRenderer: Ext.util.Format.usMoney
                }
            ],

            view: new Ext.grid.GroupingView({
                forceFit: true,
                showGroupName: false,
                enableNoGroups: false,
    			enableGroupingMenu: false,
                hideGroupedColumn: true
            }),

            plugins: summary,

            tbar : [{
                text: 'Toggle',
                tooltip: 'Toggle the visibility of summary row',
                handler: function(){summary.toggleSummaries();}
            }],

            frame: true,
            width: 800,
            height: 450,
            clicksToEdit: 1,
            collapsible: true,
            animCollapse: false,
            trackMouseOver: false,
            //enableColumnMove: false,
            title: 'Sponsored Projects',
            iconCls: 'icon-grid',
            renderTo: document.body
        });

    });

    // set up namespace for application
    Ext.ns('app.grid');
    // store dummy data in the app namespace
    app.grid.dummyData = [
        {projectId: 100, project: 'Ext Forms: Field Anchoring', taskId: 112, description: 'Integrate 2.0 Forms with 2.0 Layouts', estimate: 6, rate: 150, due:'06/24/2007'},
        {projectId: 100, project: 'Ext Forms: Field Anchoring', taskId: 113, description: 'Implement AnchorLayout', estimate: 4, rate: 150, due:'06/25/2007'},
        {projectId: 100, project: 'Ext Forms: Field Anchoring', taskId: 114, description: 'Add support for multiple types of anchors', estimate: 4, rate: 150, due:'06/27/2007'},
        {projectId: 100, project: 'Ext Forms: Field Anchoring', taskId: 115, description: 'Testing and debugging', estimate: 8, rate: 0, due:'06/29/2007'},
        {projectId: 101, project: 'Ext Grid: Single-level Grouping', taskId: 101, description: 'Add required rendering "hooks" to GridView', estimate: 6, rate: 100, due:'07/01/2007'},
        {projectId: 101, project: 'Ext Grid: Single-level Grouping', taskId: 102, description: 'Extend GridView and override rendering functions', estimate: 6, rate: 100, due:'07/03/2007'},
        {projectId: 101, project: 'Ext Grid: Single-level Grouping', taskId: 103, description: 'Extend Store with grouping functionality', estimate: 4, rate: 100, due:'07/04/2007'},
        {projectId: 101, project: 'Ext Grid: Single-level Grouping', taskId: 121, description: 'Default CSS Styling', estimate: 2, rate: 100, due:'07/05/2007'},
        {projectId: 101, project: 'Ext Grid: Single-level Grouping', taskId: 104, description: 'Testing and debugging', estimate: 6, rate: 100, due:'07/06/2007'},
        {projectId: 102, project: 'Ext Grid: Summary Rows', taskId: 105, description: 'Ext Grid plugin integration', estimate: 4, rate: 125, due:'07/01/2007'},
        {projectId: 102, project: 'Ext Grid: Summary Rows', taskId: 106, description: 'Summary creation during rendering phase', estimate: 4, rate: 125, due:'07/02/2007'},
        {projectId: 102, project: 'Ext Grid: Summary Rows', taskId: 107, description: 'Dynamic summary updates in editor grids', estimate: 6, rate: 125, due:'07/05/2007'},
        {projectId: 102, project: 'Ext Grid: Summary Rows', taskId: 108, description: 'Remote summary integration', estimate: 4, rate: 125, due:'07/05/2007'},
        {projectId: 102, project: 'Ext Grid: Summary Rows', taskId: 109, description: 'Summary renderers and calculators', estimate: 4, rate: 125, due:'07/06/2007'},
        {projectId: 102, project: 'Ext Grid: Summary Rows', taskId: 110, description: 'Integrate summaries with GroupingView', estimate: 10, rate: 125, due:'07/11/2007'},
        {projectId: 102, project: 'Ext Grid: Summary Rows', taskId: 111, description: 'Testing and debugging', estimate: 8, rate: 125, due:'07/15/2007'}
    ];