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 (!walletFrame) return;
    const QString display_name = walletModel->getDisplayName();
    setWalletActionsEnabled(true);
    rpcConsole->addWallet(walletModel);
    walletFrame->addWallet(walletModel);
    m_wallet_selector->addItem(display_name, QVariant::fromValue(walletModel));
    if (m_wallet_selector->count() == 2) {
        m_wallet_selector_label_action->setVisible(true);
        m_wallet_selector_action->setVisible(true);
    }
}
void BitcoinGUI::removeWallet(WalletModel* walletModel)
{
    if (!walletFrame) return;
    int index = m_wallet_selector->findData(QVariant::fromValue(walletModel));
    m_wallet_selector->removeItem(index);
    if (m_wallet_selector->count() == 0) {
        setWalletActionsEnabled(false);
    } else if (m_wallet_selector->count() == 1) {
        m_wallet_selector_label_action->setVisible(false);
        m_wallet_selector_action->setVisible(false);
    }
    rpcConsole->removeWallet(walletModel);
    walletFrame->removeWallet(walletModel);
    updateWindowTitle();
}
void BitcoinGUI::setCurrentWallet(WalletModel* wallet_model)