_spreadsheet.addEventListener(Events.ON_CELL_DOUBLE_CLICK, _doClearClipboard);
_spreadsheet.addEventListener(Events.ON_START_EDITING, _doClearClipboard);
if (_upload == null) {
_upload = new Upload();
_upload.appendChild(_insertPicture = new Uploader());
_insertPicture.addEventListener(org.zkoss.zk.ui.event.Events.ON_UPLOAD, new EventListener() {
@Override
public void onEvent(Event event) throws Exception {
doInsertPicture((UploadEvent)event);