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.
{
    if(walletFrame)
    {
        QToolBar *toolbar = addToolBar(tr("Tabs toolbar"));
        appToolBar = toolbar;
        toolbar->setContextMenuPolicy(Qt::PreventContextMenu);
        toolbar->setMovable(false);
        toolbar->setToolButtonStyle(Qt::ToolButtonTextBesideIcon);
        toolbar->addAction(overviewAction);
        toolbar->addAction(sendCoinsAction);
        toolbar->addAction(receiveCoinsAction);
        toolbar->addAction(historyAction);
        overviewAction->setChecked(true);
#ifdef ENABLE_WALLET
        QWidget *spacer = new QWidget();
        spacer->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
        toolbar->addWidget(spacer);
        m_wallet_selector = new QComboBox();
        connect(m_wallet_selector, static_cast<void (QComboBox::*)(int)>(&QComboBox::currentIndexChanged), this, &BitcoinGUI::setCurrentWalletBySelectorIndex);
        m_wallet_selector_label = new QLabel();
        m_wallet_selector_label->setText(tr("Wallet:") + " ");
        m_wallet_selector_label->setBuddy(m_wallet_selector);
        m_wallet_selector_label_action = appToolBar->addWidget(m_wallet_selector_label);
        m_wallet_selector_action = appToolBar->addWidget(m_wallet_selector);
        m_wallet_selector_label_action->setVisible(false);
        m_wallet_selector_action->setVisible(false);
#endif
    }
}
void BitcoinGUI::setClientModel(ClientModel *_clientModel)