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.
#endif 
        unitDisplayControl->setOptionsModel(_clientModel->getOptionsModel());
        OptionsModel* optionsModel = _clientModel->getOptionsModel();
        if (optionsModel && trayIcon) {
            
            connect(optionsModel, &OptionsModel::hideTrayIconChanged, this, &BitcoinGUI::setTrayIconVisible);
            
            setTrayIconVisible(optionsModel->getHideTrayIcon());
        }
    } else {
        
        toggleHideAction->setEnabled(false);
        if(trayIconMenu)
        {
            
            trayIconMenu->clear();
        }
        
        rpcConsole->setClientModel(nullptr);
#ifdef ENABLE_WALLET
        if (walletFrame)
        {
            walletFrame->setClientModel(nullptr);
        }
#endif 
        unitDisplayControl->setOptionsModel(nullptr);
    }
}
#ifdef ENABLE_WALLET
bool BitcoinGUI::addWallet(WalletModel *walletModel)