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.
#include <QApplication>
#include <QComboBox>
#include <QDateTime>
#include <QDesktopWidget>
#include <QDragEnterEvent>
#include <QListWidget>
#include <QMenuBar>
#include <QMessageBox>
#include <QMimeData>
#include <QProgressDialog>
#include <QSettings>
#include <QShortcut>
#include <QStackedWidget>
#include <QStatusBar>
#include <QStyle>
#include <QTimer>
#include <QToolBar>
#include <QUrlQuery>
#include <QVBoxLayout>
#include <boost/bind.hpp>
const std::string BitcoinGUI::DEFAULT_UIPLATFORM =
#if defined(Q_OS_MAC)
        "macosx"
#elif defined(Q_OS_WIN)
        "windows"
#else
        "other"
#endif
        ;
BitcoinGUI::BitcoinGUI(interfaces::Node& node, const PlatformStyle *_platformStyle, const NetworkStyle *networkStyle, QWidget *parent) :