#include <QtGui>

class ConfigWindow: public QWidget
{
public:
    ConfigWindow(): QWidget() {
        resize(320, 200);
        setWindowTitle("ConfigWindow");
    }
};

class MainWindow: public QMainWindow
{
public:
    MainWindow(): QMainWindow() {
        setWindowFlags(Qt::Tool | Qt::FramelessWindowHint);
        ConfigWindow *ConfWindow = new ConfigWindow();
        ConfWindow->show();
        setStyleSheet("background-color: blue;");
        raise();
    }
};

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    app.setQuitOnLastWindowClosed(false);

    MainWindow m;
    m.show();

    return app.exec();
}