public void event(UserRequest ureq, Component source, Event event) {
if (source == onCommand) {
// toggle on
Preferences prefs = ureq.getUserSession().getGuiPreferences();
prefs.put(CourseGlossaryToolLinkController.class, guiPrefsKey, Boolean.TRUE);
prefs.save();
// update gui
mainVC.remove(onCommand);
offCommand = LinkFactory.createLink("command.glossary.off", mainVC, this);
offCommand.setTitle("command.glossary.off.alt");
offCommand.setCustomEnabledLinkCSS("b_toolbox_toggle");