Noticed this while reviewing #13529, but it's also in master @ 5ba77df. On macOS 10.13.6:

<img width="209" alt="schermafbeelding 2018-08-01 om 16 22 09" src="https://user-images.githubusercontent.com/10217/43527498-0f571db4-95a7-11e8-8d90-7863947a7689.png">


<img width="178" alt="schermafbeelding 2018-08-01 om 16 12 51" src="https://user-images.githubusercontent.com/10217/43526994-c9a515ec-95a5-11e8-96b8-9e2513e9aac5.png">

* `Show` in the action menu doesn't work if the app was hidden by `Command + H`, it does work when hidden through this menu
* send and receive don't unhide the window when opened for the action menu. It does navigate to the right tab. The other actions do work (sign, verify & debug window)

Clicking "Toon" (= macOS native show) does work, suggesting the GUI uses some non-native method of hiding.
}
    
    if (!msgType.isEmpty())
        strTitle += " - " + msgType;
    
    if (style & CClientUIInterface::ICON_ERROR) {
        nMBoxIcon = QMessageBox::Critical;
        nNotifyIcon = Notificator::Critical;
    }
    else if (style & CClientUIInterface::ICON_WARNING) {
        nMBoxIcon = QMessageBox::Warning;
        nNotifyIcon = Notificator::Warning;
    }
    
    if (style & CClientUIInterface::MODAL) {
        
        QMessageBox::StandardButton buttons;
        if (!(buttons = (QMessageBox::StandardButton)(style & CClientUIInterface::BTN_MASK)))
            buttons = QMessageBox::Ok;
        showNormalIfMinimized();
        QMessageBox mBox(static_cast<QMessageBox::Icon>(nMBoxIcon), strTitle, message, buttons, this);
        mBox.setTextFormat(Qt::PlainText);
        int r = mBox.exec();
        if (ret != nullptr)
            *ret = r == QMessageBox::Ok;
    }
    else
        notificator->notify(static_cast<Notificator::Class>(nNotifyIcon), strTitle, message);
}
void BitcoinGUI::changeEvent(QEvent *e)