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.
void unsubscribeFromCoreSignals();
protected:
    void changeEvent(QEvent *e);
    void closeEvent(QCloseEvent *event);
    void showEvent(QShowEvent *event);
    void dragEnterEvent(QDragEnterEvent *event);
    void dropEvent(QDropEvent *event);
    bool eventFilter(QObject *object, QEvent *event);
private:
    interfaces::Node& m_node;
    WalletController* m_wallet_controller{nullptr};
    std::unique_ptr<interfaces::Handler> m_handler_message_box;
    std::unique_ptr<interfaces::Handler> m_handler_question;
    ClientModel* clientModel = nullptr;
    WalletFrame* walletFrame = nullptr;
    UnitDisplayStatusBarControl* unitDisplayControl = nullptr;
    QLabel* labelWalletEncryptionIcon = nullptr;
    QLabel* labelWalletHDStatusIcon = nullptr;