Run `src/qt/bitcoin-qt --disablewallet=1`. 
Quitting after any amount of time will result in `Segmentation fault: 11`

0.14.0 branch at 861cb0c83db0571c2863f6b6276314e115c266ee , osx 10.12.3, Qt5.8
{
    if (trayIcon)
    {
        trayIcon->setVisible(!fHideTrayIcon);
    }
}
void BitcoinGUI::showModalOverlay()
{
    if (modalOverlay && (progressBar->isVisible() || modalOverlay->isLayerVisible()))
        modalOverlay->toggleVisibility();
}
static bool ThreadSafeMessageBox(BitcoinGUI *gui, const std::string& message, const std::string& caption, unsigned int style)
{
    bool modal = (style & CClientUIInterface::MODAL);
    
    
    style &= ~CClientUIInterface::SECURE;
    bool ret = false;
    
    QMetaObject::invokeMethod(gui, "message",
                               modal ? GUIUtil::blockingGUIThreadConnection() : Qt::QueuedConnection,
                               Q_ARG(QString, QString::fromStdString(caption)),
                               Q_ARG(QString, QString::fromStdString(message)),
                               Q_ARG(unsigned int, style),
                               Q_ARG(bool*, &ret));
    return ret;
}
void BitcoinGUI::subscribeToCoreSignals()