title: ExtJS Assigning value to the hidden field
body: <p>I have the below combobox set to put some records through API call and then display on the page. I need to submit 2 values when user clicks submit, 1) gmiExchangeCode and 2) gmiFuturesCode. The first value works through this form's field, the gmiFuturesCode doesn't work on updating the hidden form field. </p>
  
  <pre><code>}, {
              xtype: 'combo',
              autoLoad: true,
              hideTrigger: true,
              fieldLabel: 'Product',
              displayField: 'gmiDescription',
              valueField: 'gmiExchangeCode',
              submitValue: true,
              name: 'exchange',
              queryMode: 'remote',
              queryParam: 'entry',
              typeAhead: true,
              minChar: 2,
              tpl: new Ext.XTemplate('&lt;tpl for="."&gt;&lt;div class="x-boundlist-item" style="border-bottom:1px solid #757575;"&gt;{gmiExchangeCode} - {lisaMarket} - {gmiFuturesCode} - {gmiDescription}&lt;/div&gt;&lt;/tpl&gt;'),
              store: {
                  fields: ['text', 'value'],
                  proxy: {
                      type: 'ajax',
                      url: 'API',
                      reader: {
                          type: 'json'
                      }
                  }
              },
              listeners: {
                  select: function (combo, record, index) {
                      hidden.setValue(record.get('gmiFuturesCode'));
                  }
              }
          }, {
              xtype: 'hidden',
              id: 'futures',
              name: 'futures'
          }, {
  </code></pre>