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.
{
    QActionGroup *tabGroup = new QActionGroup(this);
    overviewAction = new QAction(platformStyle->SingleColorIcon(":/icons/overview"), tr("&Overview"), this);
    overviewAction->setStatusTip(tr("Show general overview of wallet"));
    overviewAction->setToolTip(overviewAction->statusTip());
    overviewAction->setCheckable(true);
    overviewAction->setShortcut(QKeySequence(Qt::ALT + Qt::Key_1));
    tabGroup->addAction(overviewAction);
    sendCoinsAction = new QAction(platformStyle->SingleColorIcon(":/icons/send"), tr("&Send"), this);
    sendCoinsAction->setStatusTip(tr("Send coins to a Bitcoin address"));
    sendCoinsAction->setToolTip(sendCoinsAction->statusTip());
    sendCoinsAction->setCheckable(true);
    sendCoinsAction->setShortcut(QKeySequence(Qt::ALT + Qt::Key_2));
    tabGroup->addAction(sendCoinsAction);
    sendCoinsMenuAction = new QAction(platformStyle->TextColorIcon(":/icons/send"), sendCoinsAction->text(), this);
    sendCoinsMenuAction->setStatusTip(sendCoinsAction->statusTip());
    sendCoinsMenuAction->setToolTip(sendCoinsMenuAction->statusTip());
    receiveCoinsAction = new QAction(platformStyle->SingleColorIcon(":/icons/receiving_addresses"), tr("&Receive"), this);
    receiveCoinsAction->setStatusTip(tr("Request payments (generates QR codes and bitcoin: URIs)"));
    receiveCoinsAction->setToolTip(receiveCoinsAction->statusTip());
    receiveCoinsAction->setCheckable(true);
    receiveCoinsAction->setShortcut(QKeySequence(Qt::ALT + Qt::Key_3));
    tabGroup->addAction(receiveCoinsAction);
    receiveCoinsMenuAction = new QAction(platformStyle->TextColorIcon(":/icons/receiving_addresses"), receiveCoinsAction->text(), this);
    receiveCoinsMenuAction->setStatusTip(receiveCoinsAction->statusTip());