EventOrderConstraint secConstraint = secEvent.getConstraint(EventOrderConstraint.class);
if (secConstraint == null) {
secConstraint = new EventOrderConstraint(secEvent);
secEvent.putConstraint(secConstraint);
}
secConstraint.addBefore(firstEvent);
} else if (i == -1) {
// We could check now the priviously added followers and beforers,
// but this is not possible because '-1' could occur the
// first time (instead of expected '1')
}