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
{
    if(!clientModel)
        return;
    HelpMessageDialog dlg(m_node, this, true);
    dlg.exec();
}
void BitcoinGUI::showDebugWindow()
{
    GUIUtil::bringToFront(rpcConsole);
}
void BitcoinGUI::showDebugWindowActivateConsole()
{
    rpcConsole->setTabFocus(RPCConsole::TAB_CONSOLE);
    showDebugWindow();
}
void BitcoinGUI::showHelpMessageClicked()
{
    helpMessageDialog->show();
}
#ifdef ENABLE_WALLET
void BitcoinGUI::openClicked()
{
    OpenURIDialog dlg(this);
    if(dlg.exec())
    {
        Q_EMIT receivedURI(dlg.getURI());
    }
}
void BitcoinGUI::gotoOverviewPage()