MODExt checkbox

VisualTeams.combo.TeamPlayers = function(config) {
    config = config || {};
    Ext.applyIf(config,{
        name: 'teamplayers'
        ,hiddenName: 'player'
        ,displayField: 'username'
        ,valueField: 'id'
        ,fields: ['id','username']
        ,forceSelection: true
        ,typeAhead: false
        ,editable: false
        ,allowBlank: false
        ,listWidth: 300
        ,url: VisualTeams.config.connector_url
        ,baseParams: {
            action: 'mgr/players/getlist'
            ,team: MODx.request.team
            ,combo: true
        }
    });
    VisualTeams.combo.TeamPlayers.superclass.constructor.call(this,config);
};
Ext.extend(VisualTeams.combo.TeamPlayers,MODx.combo.ComboBox);
Ext.reg('visualteams-combo-teamplayers',VisualTeams.combo.TeamPlayers);

{ xtype: 'checkboxgroup'
 ,fieldLabel: _('myextra.field_label')
 ,name: 'myField'
 ,items: myArray
}

var myArray = [
  { name: "myfield[]", inputValue: "foo", boxLabel: "Foo" }
 ,{ name: "myfield[]", inputValue: "bar", boxLabel: "Bar" }
];

var myArray = new Array();                                                                                               
                                                                                                                   
var myStore = new Ext.data.JsonStore({                                                                         
   url: myExtra.config.connectorUrl                                                                               
  ,root: 'results'                                                                                                 
  ,baseParams: { action: 'mgr/myModel/getList' }                                                     
  ,fields: ["id", "title"]          
  ,autoLoad: false                                                                                                 
  ,listeners: {                                                                                                    
      load: function(t, records, options) {                                                                        
          for (var i=0; i<records.length; i++) {                                                                   
            myArray.push({name: "myfield[]", inputValue: records[i].data.id, boxLabel: records[i].data.title});                                               
          }                                                                                                        
      }                                                                                                            
  }                                                                                                                
});                                                                                                                
                                                                                                                   
myStore.load();

,{
xtype: 'panel',
title: 'Players',
layout: 'form',
items: [
{ xtype: 'checkboxgroup'
,fieldLabel: ('Players')
,name: 'myField'
,items: myArray
}
]
}

this.proxy is undefined
Observable()ext-all.js (regel 7)
e = "read"
a = undefined
c = Object { params={...}}
b = undefined
Observable()ext-all.js (regel 7)
b = Object { params={...}}
stores.js?v=210rc4()stores...=210rc4 (regel 18)
[Afbreken op deze fout] (function(){var h=Ext.util,k=Ext.each,...lclick",this.onNodeDblClick,this)}}); 

Ext.onReady(function() {

  myArray = new Array();

  // etc

});

VisualTeams.config.connector_url

Ext.onReady(function() {
    myArray = new Array();
    var myStore = new Ext.data.JsonStore({

    // code removed

    myStore.load(); 
});

MyCmp.panel.Section = function(config) {
    config = config || {record:{}};
     
    // code removed

    {
	xtype: 'checkboxgroup'
	,fieldLabel: 'Features'
	,items: myArray
    }