If the main window has been minimized to the taskbar (iconified) calling "Show/Hide", "Send" or "Receive" actions from the tray icon menu has no effect: the main window still minimized.

It seems like a Qt bug similar to that old [one](https://bugreports.qt.io/browse/QTBUG-31117).

Tested platform: Linux Mint 19, Qt 5.9.5 / 5.9.6
{
#ifndef Q_OS_MAC
    
    if (!trayIcon)
        return;
    trayIconMenu = new QMenu(this);
    trayIcon->setContextMenu(trayIconMenu);
    connect(trayIcon, &QSystemTrayIcon::activated, this, &BitcoinGUI::trayIconActivated);
#else
    
    MacDockIconHandler *dockIconHandler = MacDockIconHandler::instance();
    connect(dockIconHandler, &MacDockIconHandler::dockIconClicked, this, &BitcoinGUI::macosDockIconActivated);
    trayIconMenu = new QMenu(this);
    trayIconMenu->setAsDockMenu();
#endif
    
#ifndef Q_OS_MAC
    
    trayIconMenu->addAction(toggleHideAction);
    trayIconMenu->addSeparator();
#endif
    if (enableWallet) {
        trayIconMenu->addAction(sendCoinsMenuAction);
        trayIconMenu->addAction(receiveCoinsMenuAction);
        trayIconMenu->addSeparator();
        trayIconMenu->addAction(signMessageAction);
        trayIconMenu->addAction(verifyMessageAction);