Using master (98958c81f5065a5de13699d46995d278ecb6709e) with Qt `5.12.3` (also tested with depends) with multiple wallets available. None are shown in the `Open Wallet ->` menu in the gui. The wallets can be loaded from the console, bitcoin-cli etc.
{
    QMainWindow::changeEvent(e);
#ifndef Q_OS_MAC 
    if(e->type() == QEvent::WindowStateChange)
    {
        if(clientModel && clientModel->getOptionsModel() && clientModel->getOptionsModel()->getMinimizeToTray())
        {
            QWindowStateChangeEvent *wsevt = static_cast<QWindowStateChangeEvent*>(e);
            if(!(wsevt->oldState() & Qt::WindowMinimized) && isMinimized())
            {
                QTimer::singleShot(0, this, &BitcoinGUI::hide);
                e->ignore();
            }
            else if((wsevt->oldState() & Qt::WindowMinimized) && !isMinimized())
            {
                QTimer::singleShot(0, this, &BitcoinGUI::show);
                e->ignore();
            }
        }
    }
#endif
}
void BitcoinGUI::closeEvent(QCloseEvent *event)