extjs4 多层表头

有用过extjs4的朋友吗。帮忙看下列为什么没有平铺，挤在一起了呢？ 
var tree = Ext.create('Ext.tree.Panel', {
        title: 'Core Team Projects',
        width: 1060,
        height: 300,
        renderTo: Ext.getBody(),
        collapsible: true,
        useArrows: true,
        rootVisible: false,
        store: store,
        multiSelect: true,
        singleExpand: true,
         suspendLayout:false,
              columns: [
{text: '机构编号', sortable: false, dataIndex: 'id', hidden:true},{xtype: 'treecolumn', text: '机构名称', sortable: false,  width:100,dataIndex: 'brhName'},[{text: '金融类',columns:[{text: '汇兑', width:80,dataIndex:'title9', sortable: false, align:'center'},{text: '保险', width:80,dataIndex:'title7', sortable: false, align:'center'},{text: '储蓄', width:80,dataIndex:'title8', sortable: false, align:'center'}]},{text: '金融类合计', width:90,dataIndex:'title5', sortable: false, align:'center'},{text: '邮务类',columns:[{text: '函件', width:80,dataIndex:'title2', sortable: false, align:'center'},{text: 'EMS',columns:[{text: '服务类',columns:[{text: '投递时限', width:80,dataIndex:'title11', sortable: false, align:'center'},{text: '网点服务', width:80,dataIndex:'title10', sortable: false, align:'center'}]},{text: '服务类合计', width:190,dataIndex:'title21', sortable: false, align:'center'}]},{text: 'EMS合计', width:90,dataIndex:'title6', sortable: false, align:'center'},{text: '包裹', width:80,dataIndex:'title3', sortable: false, align:'center'},{text: '在睦', width:80,dataIndex:'title61', sortable: false, align:'center'}]},{text: '邮务类合计', width:90,dataIndex:'title4', sortable: false, align:'center'}]
]
    });