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.
{
#ifdef Q_OS_MAC
    
    appMenuBar = new QMenuBar();
#else
    
    appMenuBar = menuBar();
#endif
    
    QMenu *file = appMenuBar->addMenu(tr("&File"));
    if(walletFrame)
    {
        file->addAction(openAction);
        file->addAction(backupWalletAction);
        file->addAction(signMessageAction);
        file->addAction(verifyMessageAction);
        file->addSeparator();
    }
    file->addAction(quitAction);
    QMenu *settings = appMenuBar->addMenu(tr("&Settings"));
    if(walletFrame)
    {
        settings->addAction(encryptWalletAction);