*/
private void enableListening(IErrorStrategy ies, boolean listen) {
if (ies instanceof ErrorStrategyModel) { // this test returns false if ies is null
ErrorStrategyModel esm = (ErrorStrategyModel) ies;
if (listen) {
esm.addListener(listenerErrorStrategy);
}
else {
esm.removeListener(listenerErrorStrategy);
}
enableListening(esm.getActuatorsErrorStrategy(), listen);