public void event(UserRequest ureq, Component source, Event event) {
if (source == previewLink){
removeAsListenerAndDispose(previewLayoutCtr);
SinglePageController previewController = new SinglePageController(ureq, getWindowControl(), iframeEnabled, rootContainer, chosenFile, null, allowRelativeLinks.booleanValue(), showHomeLink);
previewLayoutCtr = new LayoutMain3ColsPreviewController(ureq, getWindowControl(), null, null, previewController.getInitialComponent(), null);
previewLayoutCtr.addDisposableChildController(previewController);
previewLayoutCtr.activate();
listenTo(previewLayoutCtr);
}
// edit chosen file