public void event(UserRequest ureq, Component source, Event event) {
if (log.isDebug()) log.debug("event source=" + source + " " + event.toString());
if (source == btfButton){
// check if there are already assigned tasks
CoursePropertyManager cpm = PersistingCoursePropertyManager.getInstance(course);
List assignedProps = cpm.listCourseNodeProperties(node, null, null, TaskController.PROP_ASSIGNED);
if (assignedProps.size() == 0) {
// no task assigned
String relPath = TACourseNode.getTaskFolderPathRelToFolderRoot(course, node);
OlatRootFolderImpl rootFolder = new OlatRootFolderImpl(relPath, null);
OlatNamedContainerImpl namedFolder = new OlatNamedContainerImpl(translate("taskfolder"), rootFolder);