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.
{
    
    if(event->mimeData()->hasUrls())
        event->acceptProposedAction();
}
void BitcoinGUI::dropEvent(QDropEvent *event)
{
    if(event->mimeData()->hasUrls())
    {
        for (const QUrl &uri : event->mimeData()->urls())
        {
            Q_EMIT receivedURI(uri.toString());
        }
    }
    event->acceptProposedAction();
}
bool BitcoinGUI::eventFilter(QObject *object, QEvent *event)