ExtJS3.0 的 grouptabs 问题

看示例得知:左边为导航栏,右侧为内容栏,
看这代码后有这样的一个想法,可不可以点击左侧的链接或者按钮右侧显示页面呢.
JS源示例如下:var viewport = new Ext.Viewport({
        layout:'fit',
        items:[{
            xtype: 'grouptabpanel',
            tabWidth: 130,
            activeGroup: 0,
            items: [{
                mainItem: 1,
                items: [{
                    title: 'Tickets',
                    layout: 'fit',
                    iconCls: 'x-icon-tickets',
                    tabTip: 'Tickets tabtip',
                    style: 'padding: 10px;',
                    items: [new SampleGrid([0,1,2,3,4])]
                },
                {
                    xtype: 'portal',
                    title: 'Dashboard',
                    tabTip: 'Dashboard tabtip',
                    items:[{
                        columnWidth:.33,
                        style:'padding:10px 0 10px 10px',
                        items:[{
                            title: 'Grid in a Portlet',
                            layout:'fit',
                            tools: tools,
                            items: new SampleGrid([0, 2, 3])
                        },{
                            title: 'Another Panel 1',
                            tools: tools,
                            html: Ext.example.shortBogusMarkup
                        }]
                    },{
                        columnWidth:.33,
                        style:'padding:10px 0 10px 10px',
                        items:[{
                            title: 'Panel 2',
                            tools: tools,
                            html: Ext.example.shortBogusMarkup
                        },{
                            title: 'Another Panel 2',
                            tools: tools,
                            html: Ext.example.shortBogusMarkup
                        }]
                    },{
                        columnWidth:.33,
                        style:'padding:10px',
                        items:[{
                            title: 'Panel 3',
                            tools: tools,
                            html: Ext.example.shortBogusMarkup
                        },{
                            title: 'Another Panel 3',
                            tools: tools,
                            html: Ext.example.shortBogusMarkup
                        }]
                    }]                    
                }, {
                    title: 'Subscriptions',
                    iconCls: 'x-icon-subscriptions',
                    tabTip: 'Subscriptions tabtip',
                    style: 'padding: 10px;',
                    layout: 'fit',
                    items: [{
                        xtype: 'tabpanel',
                        activeTab: 1,
                        items: [{
                            title: 'Nested Tabs',
                            html: Ext.example.shortBogusMarkup
                        }]
                    }]
                }, {
                    title: 'Users',
                    iconCls: 'x-icon-users',
                    tabTip: 'Users tabtip',
                    style: 'padding: 10px;',
                    html: Ext.example.shortBogusMarkup
                }]
            }, {
                expanded: true,
                items: [{
                    title: 'Configuration',
                    iconCls: 'x-icon-configuration',
                    tabTip: 'Configuration tabtip',
                    style: 'padding: 10px;',
                    html: Ext.example.shortBogusMarkup 
                }, {
                    title: 'Email Templates',
                    iconCls: 'x-icon-templates',
                    tabTip: 'Templates tabtip',
                    style: 'padding: 10px;',
                    html: Ext.example.shortBogusMarkup
                }]
            }]
        }]
    });
这里的html属性指的是右侧页中的内容
按照我的想法我想问一下EXTJS高手们,应该如何更改
我想改成.点击左侧的链接后,右面内容页显示 例如http://www.baidu.com这个网址的内容.请教大家应该如何更改.
默认的html是文本或者EXT的对象.