code: function(el, prefix) {
          var me = this,
              sandboxPrefix = '';
          el = Ext.getDom(el, true) || {};
          if (el === document) {
              el.id = me.documentId;
          }
          else if (el === window) {
              el.id = me.windowId;
          }
          if (!el.id) {
              if (me.isSandboxed) {
                  sandboxPrefix = Ext.sandboxName.toLowerCase() + '-';
              }
              el.id = sandboxPrefix + (prefix || "ext-gen") + (++Ext.idSeed);
          }
          return el.id;
      }
docs: Generates unique ids. If the element already has an id, it is unchanged
  @param {HTMLElement/Ext.Element} [el] The element to generate an id for
  @param {String} prefix (optional) Id prefix (defaults "ext-gen")
  @return {String} The generated Id.