save.setStyleName(STYLE_NAME_BUTTON);
save.addClickHandler(new ClickHandler() {
@Override
public void onClick(ClickEvent event) {
callback.toBeSaved(wikiPageArea.getText(), new AsyncCallback<Boolean>() {
@Override
public void onSuccess(Boolean result) {
if (result == null)
Window.alert("Seite kann leider nicht gespeichert werden: unerwarteter Rückgabewert (result == null");