<!-- Describe the issue -->
Hello evryone, I get nothing when I click in open wallet, I am new to bitcoin and expect to show something.

![BitcoinIssue](https://user-images.githubusercontent.com/39341595/57179721-5024fc00-6e9e-11e9-80dd-af5e4345be48.png)

I'am using Bitcoin Core (both in testnet and mainnet, didn't work) 0.18 on window 10. 

connect(aboutQtAction, &QAction::triggered, qApp, QApplication::aboutQt);
    connect(optionsAction, &QAction::triggered, this, &BitcoinGUI::optionsClicked);
    connect(toggleHideAction, &QAction::triggered, this, &BitcoinGUI::toggleHidden);
    connect(showHelpMessageAction, &QAction::triggered, this, &BitcoinGUI::showHelpMessageClicked);
    connect(openRPCConsoleAction, &QAction::triggered, this, &BitcoinGUI::showDebugWindow);
    
    connect(quitAction, &QAction::triggered, rpcConsole, &QWidget::hide);
#ifdef ENABLE_WALLET
    if(walletFrame)
    {
        connect(encryptWalletAction, &QAction::triggered, walletFrame, &WalletFrame::encryptWallet);
        connect(backupWalletAction, &QAction::triggered, walletFrame, &WalletFrame::backupWallet);
        connect(changePassphraseAction, &QAction::triggered, walletFrame, &WalletFrame::changePassphrase);
        connect(signMessageAction, &QAction::triggered, [this]{ showNormalIfMinimized(); });
        connect(signMessageAction, &QAction::triggered, [this]{ gotoSignMessageTab(); });
        connect(verifyMessageAction, &QAction::triggered, [this]{ showNormalIfMinimized(); });
        connect(verifyMessageAction, &QAction::triggered, [this]{ gotoVerifyMessageTab(); });
        connect(usedSendingAddressesAction, &QAction::triggered, walletFrame, &WalletFrame::usedSendingAddresses);
        connect(usedReceivingAddressesAction, &QAction::triggered, walletFrame, &WalletFrame::usedReceivingAddresses);
        connect(openAction, &QAction::triggered, this, &BitcoinGUI::openClicked);
        connect(m_open_wallet_action->menu(), &QMenu::aboutToShow, [this] {
            m_open_wallet_action->menu()->clear();
            for (std::string path : m_wallet_controller->getWalletsAvailableToOpen()) {
                QString name = path.empty() ? QString("["+tr("default wallet")+"]") : QString::fromStdString(path);
                QAction* action = m_open_wallet_action->menu()->addAction(name);
                connect(action, &QAction::triggered, [this, name, path] {
                    OpenWalletActivity* activity = m_wallet_controller->openWallet(path);
                    QProgressDialog* dialog = new QProgressDialog(this);
                    dialog->setLabelText(tr("Opening Wallet <b>%1</b>...").arg(name.toHtmlEscaped()));
                    dialog->setRange(0, 0);