code: function(id) {
          if (typeof id !== "string") {
              YAHOO.log("id is not a string, assuming it is an HTMLElement");
              id = Dom.generateId(id);
          }
          this.invalidHandleIds[id] = id;
      }
docs: Lets you to specify an element id for a child of a drag handle
  that should not initiate a drag
  @method addInvalidHandleId
  @param {string} id the element id of the element you wish to ignore