NormalTask task = (NormalTask)i.next();
// if (!task.isAssignable())
// continue;
if (transactionId == 0) {
transactionProject = task.getProject();
transactionProject.beginUndoUpdate();
transactionId = transactionProject.fireMultipleTransaction(0,true);
//backup before any assignment operation
transactionProject.getUndoController().getEditSupport().postEdit(new ScheduleBackupEdit(tasks,this));
}