this.item.stopObservingCurrency(currencyObserver);
this.item.getModel().showCurrency.removeObserver(showCurrencyObserver);
this.item.stopObservingComment(commentObserver);
this.item.stopObservingCurrency(currencyObserver);
this.item.getModel().showCurrency.removeObserver(showCurrencyObserver);
this.item.stopObservingComment(commentObserver);