toField.setValidators(notNull(), notEmpty());
ShortTextField subjectField = new ShortTextField("subject", "Subject:");
subjectField.setValidators(notNull(), notEmpty());
LongTextField bodyField = new LongTextField("body", "Body:");
bodyField.setValidators(notNull(), notEmpty());
final Form form = new Form();
form.addFields(toField, subjectField, bodyField);
FieldGroup group = new FieldGroup("to", "subject", "body");