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 (nProgress == 0)
    {
        progressDialog = new QProgressDialog(title, "", 0, 100);
        progressDialog->setWindowModality(Qt::ApplicationModal);
        progressDialog->setMinimumDuration(0);
        progressDialog->setCancelButton(0);
        progressDialog->setAutoClose(false);
        progressDialog->setValue(0);
    }
    else if (nProgress == 100)
    {
        if (progressDialog)
        {
            progressDialog->close();
            progressDialog->deleteLater();
        }
    }
    else if (progressDialog)
        progressDialog->setValue(nProgress);
}
void BitcoinGUI::setTrayIconVisible(bool fHideTrayIcon)