The part of the GUI that this setting is relevant for does not exist in a `--disable-wallet` build. 

![wallet_prefs](https://user-images.githubusercontent.com/863730/70331435-72547300-180d-11ea-842d-82f8529ae982.png)
else
        {
            
            ui->lang->addItem(locale.nativeLanguageName() + QString(" (") + langStr + QString(")"), QVariant(langStr));
        }
    }
    ui->thirdPartyTxUrls->setPlaceholderText("https://example.com/tx/%s");
    ui->unit->setModel(new BitcoinUnits(this));
    
    mapper = new QDataWidgetMapper(this);
    mapper->setSubmitPolicy(QDataWidgetMapper::ManualSubmit);
    mapper->setOrientation(Qt::Vertical);
    GUIUtil::ItemDelegate* delegate = new GUIUtil::ItemDelegate(mapper);
    connect(delegate, &GUIUtil::ItemDelegate::keyEscapePressed, this, &OptionsDialog::reject);
    mapper->setItemDelegate(delegate);
    
    ui->proxyIp->setCheckValidator(new ProxyAddressValidator(parent));
    ui->proxyIpTor->setCheckValidator(new ProxyAddressValidator(parent));
    connect(ui->proxyIp, &QValidatedLineEdit::validationDidChange, this, &OptionsDialog::updateProxyValidationState);
    connect(ui->proxyIpTor, &QValidatedLineEdit::validationDidChange, this, &OptionsDialog::updateProxyValidationState);
    connect(ui->proxyPort, &QLineEdit::textChanged, this, &OptionsDialog::updateProxyValidationState);
    connect(ui->proxyPortTor, &QLineEdit::textChanged, this, &OptionsDialog::updateProxyValidationState);
    if (!QSystemTrayIcon::isSystemTrayAvailable()) {
        ui->hideTrayIcon->setChecked(true);
        ui->hideTrayIcon->setEnabled(false);
        ui->minimizeToTray->setChecked(false);
        ui->minimizeToTray->setEnabled(false);
    }
}
OptionsDialog::~OptionsDialog()