MultiComboBox(多选下拉问题)

MultiComboBox多选下拉问题初始化时不能选中，有会用的请指导一下


var taskstatuscombo = new Ext.form.MultiComboBox({
  xtype : "multicombo",
  width:200,
  id : "tf_orderState",
  store:new Ext.data.JsonStore({
url : SPM_PATH+ "/spm/DictionarieAction.do?method=getDictionaryList&dictionaryType=1",
fields : ["value", "name"],
autoLoad : true,
listeners : {
load : function(store, records, options) {
Ext.getCmp("tf_orderState").setValue(Ext.getCmp("tf_orderState").getValue());
}
}
}),
   valueField :"value",
   displayField: "name",
   labelSeparator:'：',
   displaySeparator:';',
   valueSeparator:',',
   mode: 'local',
   forceSelection: true,
   hiddenName:'value',
   editable: true,
   triggerAction: 'all',
   allowBlank:false,
   emptyText:'请选择'
  });