Noticed this while reviewing #13529, but it's also in master @ 5ba77df. On macOS 10.13.6:

<img width="209" alt="schermafbeelding 2018-08-01 om 16 22 09" src="https://user-images.githubusercontent.com/10217/43527498-0f571db4-95a7-11e8-8d90-7863947a7689.png">


<img width="178" alt="schermafbeelding 2018-08-01 om 16 12 51" src="https://user-images.githubusercontent.com/10217/43526994-c9a515ec-95a5-11e8-96b8-9e2513e9aac5.png">

* `Show` in the action menu doesn't work if the app was hidden by `Command + H`, it does work when hidden through this menu
* send and receive don't unhide the window when opened for the action menu. It does navigate to the right tab. The other actions do work (sign, verify & debug window)

Clicking "Toon" (= macOS native show) does work, suggesting the GUI uses some non-native method of hiding.
{
    if (!walletFrame) {
        return;
    }
    WalletView * const walletView = walletFrame->currentWalletView();
    if (!walletView) {
        return;
    }
    WalletModel * const walletModel = walletView->getWalletModel();
    setEncryptionStatus(walletModel->getEncryptionStatus());
    setHDStatus(walletModel->wallet().hdEnabled());
}
#endif 
void BitcoinGUI::updateProxyIcon()
{
    std::string ip_port;
    bool proxy_enabled = clientModel->getProxyInfo(ip_port);
    if (proxy_enabled) {
        if (labelProxyIcon->pixmap() == 0) {
            QString ip_port_q = QString::fromStdString(ip_port);
            labelProxyIcon->setPixmap(platformStyle->SingleColorIcon(":/icons/proxy").pixmap(STATUSBAR_ICONSIZE, STATUSBAR_ICONSIZE));
            labelProxyIcon->setToolTip(tr("Proxy is <b>enabled</b>: %1").arg(ip_port_q));
        } else {
            labelProxyIcon->show();
        }
    } else {
        labelProxyIcon->hide();
    }
}
void BitcoinGUI::showNormalIfMinimized(bool fToggleHidden)