Compile master, and run with `src/qt/bitcoin-qt -regtest -nowallet`. As expected, no icon is displayed. Load and unload a wallet. The `HD` icon remains.

On startup:
![on_startup](https://user-images.githubusercontent.com/863730/72410834-711b4c00-37a4-11ea-9a10-bfcf3db7ce68.png)

After a wallet load and unload:
![after_load_unload](https://user-images.githubusercontent.com/863730/72410838-737da600-37a4-11ea-8854-dd13301c0135.png)

{
    QString window_title = PACKAGE_NAME;
#ifdef ENABLE_WALLET
    if (walletFrame) {
        WalletModel* const wallet_model = walletFrame->currentWalletModel();
        if (wallet_model && !wallet_model->getWalletName().isEmpty()) {
            window_title += " - " + wallet_model->getDisplayName();
        }
    }
#endif
    if (!m_network_style->getTitleAddText().isEmpty()) {
        window_title += " - " + m_network_style->getTitleAddText();
    }
    setWindowTitle(window_title);
}
void BitcoinGUI::showNormalIfMinimized(bool fToggleHidden)
{
    if(!clientModel)
        return;
    if (!isHidden() && !isMinimized() && !GUIUtil::isObscured(this) && fToggleHidden) {
        hide();
    } else {
        GUIUtil::bringToFront(this);
    }
}
void BitcoinGUI::toggleHidden()
{
    showNormalIfMinimized(true);
}
void BitcoinGUI::detectShutdown()