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.
receiveCoinsMenuAction->setToolTip(receiveCoinsMenuAction->statusTip());
    historyAction = new QAction(platformStyle->SingleColorIcon(":/icons/history"), tr("&Transactions"), this);
    historyAction->setStatusTip(tr("Browse transaction history"));
    historyAction->setToolTip(historyAction->statusTip());
    historyAction->setCheckable(true);
    historyAction->setShortcut(QKeySequence(Qt::ALT + Qt::Key_4));
    tabGroup->addAction(historyAction);
#ifdef ENABLE_WALLET
    
    
    connect(overviewAction, &QAction::triggered, this, static_cast<void (BitcoinGUI::*)()>(&BitcoinGUI::showNormalIfMinimized));
    connect(overviewAction, &QAction::triggered, this, &BitcoinGUI::gotoOverviewPage);
    connect(sendCoinsAction, &QAction::triggered, this, static_cast<void (BitcoinGUI::*)()>(&BitcoinGUI::showNormalIfMinimized));
    connect(sendCoinsAction, &QAction::triggered, [this]{ gotoSendCoinsPage(); });
    connect(sendCoinsMenuAction, &QAction::triggered, this, static_cast<void (BitcoinGUI::*)()>(&BitcoinGUI::showNormalIfMinimized));
    connect(sendCoinsMenuAction, &QAction::triggered, [this]{ gotoSendCoinsPage(); });
    connect(receiveCoinsAction, &QAction::triggered, this, static_cast<void (BitcoinGUI::*)()>(&BitcoinGUI::showNormalIfMinimized));
    connect(receiveCoinsAction, &QAction::triggered, this, &BitcoinGUI::gotoReceiveCoinsPage);
    connect(receiveCoinsMenuAction, &QAction::triggered, this, static_cast<void (BitcoinGUI::*)()>(&BitcoinGUI::showNormalIfMinimized));
    connect(receiveCoinsMenuAction, &QAction::triggered, this, &BitcoinGUI::gotoReceiveCoinsPage);
    connect(historyAction, &QAction::triggered, this, static_cast<void (BitcoinGUI::*)()>(&BitcoinGUI::showNormalIfMinimized));
    connect(historyAction, &QAction::triggered, this, &BitcoinGUI::gotoHistoryPage);
#endif 
    quitAction = new QAction(platformStyle->TextColorIcon(":/icons/quit"), tr("E&xit"), this);
    quitAction->setStatusTip(tr("Quit application"));
    quitAction->setShortcut(QKeySequence(Qt::CTRL + Qt::Key_Q));
    quitAction->setMenuRole(QAction::QuitRole);
    aboutAction = new QAction(platformStyle->TextColorIcon(":/icons/about"), tr("&About %1").arg(tr(PACKAGE_NAME)), this);
    aboutAction->setStatusTip(tr("Show information about %1").arg(tr(PACKAGE_NAME)));
    aboutAction->setMenuRole(QAction::AboutRole);