Construct the UI for this widget from a template, setting this.domNode.
Lookup cached version of template, and download to cache if it
isn't there already. Returns either a DomNode or a string, depending on
whether or not the template contains ${foo} replacement parameters.
called before setPreview (change is fired on input node) -
publishes a message on all input that have specified a message
identifier (ep_publishmessage)
You may override this function but don't forget to call
this.inherited("onbeforePreview", arguments);
indicates weather the html code of an navigation element needs to be reloaded after changing the navbar (some navigation elements use a different html code base for navigation bars with different orientations)