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)
    {
        QToolBar *toolbar = addToolBar(tr("Tabs toolbar"));
        appToolBar = toolbar;
        toolbar->setContextMenuPolicy(Qt::PreventContextMenu);
        toolbar->setMovable(false);
        toolbar->setToolButtonStyle(Qt::ToolButtonTextBesideIcon);
        toolbar->addAction(overviewAction);
        toolbar->addAction(sendCoinsAction);
        toolbar->addAction(receiveCoinsAction);
        toolbar->addAction(historyAction);
        overviewAction->setChecked(true);
#ifdef ENABLE_WALLET
        QWidget *spacer = new QWidget();
        spacer->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
        toolbar->addWidget(spacer);
        m_wallet_selector = new QComboBox();
        connect(m_wallet_selector, static_cast<void (QComboBox::*)(int)>(&QComboBox::currentIndexChanged), this, &BitcoinGUI::setCurrentWalletBySelectorIndex);
        m_wallet_selector_label = new QLabel();
        m_wallet_selector_label->setText(tr("Wallet:") + " ");
        m_wallet_selector_label->setBuddy(m_wallet_selector);
        m_wallet_selector_label_action = appToolBar->addWidget(m_wallet_selector_label);
        m_wallet_selector_action = appToolBar->addWidget(m_wallet_selector);
        m_wallet_selector_label_action->setVisible(false);
        m_wallet_selector_action->setVisible(false);
#endif
    }
}
void BitcoinGUI::setClientModel(ClientModel *_clientModel)