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.
GUIUtil::ClickableLabel* labelProxyIcon = nullptr;
    GUIUtil::ClickableLabel* connectionsControl = nullptr;
    GUIUtil::ClickableLabel* labelBlocksIcon = nullptr;
    QLabel* progressBarLabel = nullptr;
    GUIUtil::ClickableProgressBar* progressBar = nullptr;
    QProgressDialog* progressDialog = nullptr;
    QMenuBar* appMenuBar = nullptr;
    QToolBar* appToolBar = nullptr;
    QAction* overviewAction = nullptr;
    QAction* historyAction = nullptr;
    QAction* quitAction = nullptr;
    QAction* sendCoinsAction = nullptr;
    QAction* sendCoinsMenuAction = nullptr;
    QAction* usedSendingAddressesAction = nullptr;
    QAction* usedReceivingAddressesAction = nullptr;
    QAction* signMessageAction = nullptr;
    QAction* verifyMessageAction = nullptr;
    QAction* aboutAction = nullptr;
    QAction* receiveCoinsAction = nullptr;
    QAction* receiveCoinsMenuAction = nullptr;
    QAction* optionsAction = nullptr;
    QAction* toggleHideAction = nullptr;
    QAction* encryptWalletAction = nullptr;
    QAction* backupWalletAction = nullptr;
    QAction* changePassphraseAction = nullptr;
    QAction* aboutQtAction = nullptr;
    QAction* openRPCConsoleAction = nullptr;
    QAction* openAction = nullptr;
    QAction* showHelpMessageAction = nullptr;
    QAction* m_open_wallet_action{nullptr};