Noticed this while reviewing #13529, but it's also in master @ 5ba77df15. On macOS 10.13.6:

```
bitcoin-qt -disablewallet
```

<img width="1354" alt="schermafbeelding 2018-08-01 om 16 03 41" src="https://user-images.githubusercontent.com/10217/43526506-b23264d8-95a4-11e8-81a0-5debcad838ae.png">

The usual progress modal doesn't appear when QT starts, and clicking on the progress bar has no effect. It works fine when there's a wallet present.
{
#ifndef Q_OS_MAC
    
    if (!trayIcon)
        return;
    trayIconMenu = new QMenu(this);
    trayIcon->setContextMenu(trayIconMenu);
    connect(trayIcon, &QSystemTrayIcon::activated, this, &BitcoinGUI::trayIconActivated);
#else
    
    MacDockIconHandler *dockIconHandler = MacDockIconHandler::instance();
    connect(dockIconHandler, &MacDockIconHandler::dockIconClicked, this, &BitcoinGUI::macosDockIconActivated);
    trayIconMenu = new QMenu(this);
    trayIconMenu->setAsDockMenu();
#endif
    
#ifndef Q_OS_MAC
    
    trayIconMenu->addAction(toggleHideAction);
    trayIconMenu->addSeparator();
#endif
    if (enableWallet) {
        trayIconMenu->addAction(sendCoinsMenuAction);
        trayIconMenu->addAction(receiveCoinsMenuAction);
        trayIconMenu->addSeparator();
        trayIconMenu->addAction(signMessageAction);
        trayIconMenu->addAction(verifyMessageAction);