code: function(index, silent) {
          var me = this;
  
          if (!index) {
              index = 0;
          } else if (!Ext.isNumber(index)) {
              index = Ext.Array.indexOf(me.items, index);
          }
          me.items[index].disabled = false;
          me.up('tablepanel').el.select('.' + Ext.baseCSSPrefix + 'action-col-' + index).removeCls(me.disabledCls);
          if (!silent) {
              me.fireEvent('enable', me);
          }
      }
docs: Enables this ActionColumn's action at the specified index.
  @param {Number/Ext.grid.column.Action} index
  @param {Boolean} [silent=false]