code: function() {
          var me = this,
              picker = me.picker,
              store = picker.store,
              value = me.value,
              node;
  
          
          if (value) {
              node = store.getNodeById(value);
          }
          
          if (!node) {
              node = store.getRootNode();
          }
          
          picker.selectPath(node.getPath());
  
          Ext.defer(function() {
              picker.getView().focus();
          }, 1);
      }
docs: Runs when the picker is expanded.  Selects the appropriate tree node based on the value of the input element,
  and focuses the picker so that keyboard navigation will work.
  @private