title: Reload a ComboBox store on trigger click Extjs 3.4
body: <p>I'm a beginner on <code>js</code> and ExtJS 3.4, I'm trying to use <code>Ext.form.ComboBox</code>in a Ext.window to show the list of <code>js</code> objects (layers). </p>
  
  <p>The problem is when I create the window the first time and I click on the <code>combobox</code> trigger I get my layers list correctly, but when I remove or add a layer and I click again on the trigger the store don't update and I find the same list.</p>
  
  <p>Can you please help me to find a solution to this problem, for example when I click on the trigger it will update and load the new list store ? </p>
  
  <p>Any suggestion is welcome.</p>
  
  <p><strong>CODE SNIPPET</strong></p>
  
  <pre><code>// The "ImageField" is an item witch is called on the return of the methode "createWindow" ...
  createWindow: function() {
  
      ImageField = new Ext.form.ComboBox(Ext.apply({
          name: "Image_ref",
          fieldLabel: "Image Input (Required)",
          emptyText: "Select your Image",
          xtype: 'combo',
          forceSelection: true,
          editable: true,
          allowBlank: true,
          triggerAction: 'all',
          mode: 'local',
          valueField: 'value',
          displayField: 'text',
          labelWidth: 300
          width: 250,
          id: 'myCombo',
          hideLabel: false,
          lazyRender: false,
          lazyInit: false,
          mode: 'local',
          triggerAction: 'all',
  
  
          store: new Ext.data.SimpleStore({
              autoLoad: true,
              autoDestroy: true,
              fields: ['text', 'value'],
              data: layer_liste_WCS // is a liste of js objects
          }),
          listeners: {
  
              beforequery: function(qe) {
                  // console.log(qe);
                  qe.cancel = true;
                  addComboxFieldItemsWCS(); // Run this methode to get "layer_liste_WCS" witch is liste of data
                  var actionComboBox = Ext.getCmp('myCombo');
                  .
                  .
                  .
                  .
                  .
                  .
                  // I don't know how to do to reload the store after runing the methode "addComboxFieldItemsWCS"
              }
          }
  
      }, base));
  
      return new Ext.Window({
          closable: true,
          resizable: false,
          shadow: false,
          closeAction: 'hide',
          region: "center", //"north","south","east","west"
          width: 480,
          height: 190,
          iconCls: 'wind_icon',
          plain: true,
          layout: 'border',
          buttonAlign: 'right',
          layout: 'fit',
          listeners: {
              show: function() {
                  this.el.setStyle('left', '');
                  this.el.setStyle('top', '');
              }
          },
          items: [{
              region: 'center',
              xtype: 'tabpanel',
              activeTab: 0,
              width: 50,
              height: 20,
              items: [{ // we will declare 3 tabs
                  title: 'Datas Inputs',
                  closable: false,
                  iconCls: 'input_icon',
                  active: true,
                  items: [{
                      xtype: 'form',
                      autoWidth: true,
                      labelWidth: 185,
                      bodyStyle: "padding:10px;",
                      items: [
                          ImageField,
                      ]
                  }]
              }]
          }],
      });
  },
  </code></pre>