code: function(moduleElement){
              moduleElement = moduleElement || this.element;
  
              // Need to get everything into the DOM if it isn't already
              if (this.header && !Dom.inDocument(this.header)) {
                  // There is a header, but it's not in the DOM yet. Need to add it.
                  var firstChild = moduleElement.firstChild;
                  if (firstChild) {
                      moduleElement.insertBefore(this.header, firstChild);
                  } else {
                      moduleElement.appendChild(this.header);
                  }
              }
          }
docs: Renders the currently set header into it's proper position under the
  module element. If the module element is not provided, "this.element"
  is used.
  
  @method _renderHeader
  @protected
  @param {HTMLElement} moduleElement Optional. A reference to the module element