QGraphicsProxyWidget::setWindowFlags(Qt::Tool) looks the same as Qt::Window

#include <QtGui>

int main( int argc , char *argv[] )
{
    QApplication app(argc, argv) ;
    QGraphicsScene * scene = new QGraphicsScene() ;

    QMainWindow *mainWindow = new QMainWindow();
   
   QGraphicsEllipseItem *ball = scene->addEllipse(100,150,20,20,QPen(Qt::red),QBrush(Qt::darkGreen));
   ball->setFlag(QGraphicsItem::ItemIsMovable, true);

   QGraphicsProxyWidget *gpw = scene->addWidget(mainWindow);
   gpw->setGeometry( QRect(100 , 10 , 150 , 100 ));

//   gpw->setWindowFlags(Qt::Window); //these two look the same
   gpw->setWindowFlags(Qt::Tool);

   gpw->setFlag(QGraphicsItem::ItemIsMovable,true);

   QGraphicsView *view = new QGraphicsView(scene);
   view->setBackgroundBrush(Qt::darkGray);
   view->show();
   return app.exec() ;
}