It would be cool if there was an option in Bitcoin Core for disabling the system tray entirely.

{
    ui->statusLabel->clear();
}
void OptionsDialog::updateProxyValidationState()
{
    QValidatedLineEdit *pUiProxyIp = ui->proxyIp;
    QValidatedLineEdit *otherProxyWidget = (pUiProxyIp == ui->proxyIpTor) ? ui->proxyIp : ui->proxyIpTor;
    if (pUiProxyIp->isValid() && (!ui->proxyPort->isEnabled() || ui->proxyPort->text().toInt() > 0) && (!ui->proxyPortTor->isEnabled() || ui->proxyPortTor->text().toInt() > 0))
    {
        setOkButtonState(otherProxyWidget->isValid()); 
        ui->statusLabel->clear();
    }
    else
    {
        setOkButtonState(false);
        ui->statusLabel->setStyleSheet("QLabel { color: red; }");
        ui->statusLabel->setText(tr("The supplied proxy address is invalid."));
    }
}
void OptionsDialog::updateDefaultProxyNets()