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.
{
    overviewAction->setEnabled(enabled);
    sendCoinsAction->setEnabled(enabled);
    sendCoinsMenuAction->setEnabled(enabled);
    receiveCoinsAction->setEnabled(enabled);
    receiveCoinsMenuAction->setEnabled(enabled);
    historyAction->setEnabled(enabled);
    encryptWalletAction->setEnabled(enabled);
    backupWalletAction->setEnabled(enabled);
    changePassphraseAction->setEnabled(enabled);
    signMessageAction->setEnabled(enabled);
    verifyMessageAction->setEnabled(enabled);
    usedSendingAddressesAction->setEnabled(enabled);
    usedReceivingAddressesAction->setEnabled(enabled);
    openAction->setEnabled(enabled);
}
void BitcoinGUI::createTrayIcon(const NetworkStyle *networkStyle)
{
#ifndef Q_OS_MAC
    trayIcon = new QSystemTrayIcon(this);
    QString toolTip = tr("%1 client").arg(tr(PACKAGE_NAME)) + " " + networkStyle->getTitleAddText();
    trayIcon->setToolTip(toolTip);
    trayIcon->setIcon(networkStyle->getTrayAndWindowIcon());
    trayIcon->hide();
#endif
    notificator = new Notificator(QApplication::applicationName(), trayIcon, this);
}
void BitcoinGUI::createTrayIconMenu()