ExtJS 4.1 MVC detect splitbutton's menu's 'click' event

[panbayi]

How can I detect the 'click' event of a splitbutton's menu in a controller?
For example,I have splitbutton

{
  xtype : 'splitbutton',
  icon-Cls: 'mycls',
  text: 'mysplitbutton',
  menu : {
    items : [ 
      {text : 'button A',action : 'A'},
      {text : 'button B',action : 'B'}
    ]
  }
}

I cannot detect the button A or button B in controller like this

....some code....
init : function(){
  this.control({
     'button[action=A]' : {
       click : this.myFucntionToButtonA
      }
  });
}

[panbayi]

Eh....,it's solves.I should have added 'xtype : "button" 'in each item property.