Can QDockWidget be semi-transparent?

[PolyVox]

Hi Guys,

I can't seem to make my QDockWidget semi-transparent, and was wondering if it is possible? Here is my code:

int main(int argc, char *argv[])
{
	QApplication app(argc, argv);
 
	//The main window just has a label in it's center
	QMainWindow* mainWindow = new QMainWindow(0,0);
	QLabel* mainLabel = new QLabel("Main Widget Label", mainWindow);
	mainWindow->setCentralWidget(mainLabel);
 
	//This dock window should appear 50% transparent. Instead it is fully opaque.
	QDockWidget* dockWidget = new QDockWidget("Dock Widget", mainWindow);
	QPushButton* pushButton = new QPushButton("Dock Widget Button", dockWidget);	
	dockWidget->setWidget(pushButton);
	dockWidget->setWindowOpacity(0.5);
	mainWindow->addDockWidget(Qt::LeftDockWidgetArea, dockWidget); 
 
	//Just to show transparent can work, this seperate widget does show up 50% transparent.
	QWidget *w = new QWidget(0,0);
	QPushButton* floatingPushButton = new QPushButton("Floating Widget Button", w);
	w->setWindowOpacity(0.5);
 
	//Show the windows.
	mainWindow->show();
	w->show();
 
	return app.exec();
}

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

	//The main window just has a label in it's center
	QMainWindow* mainWindow = new QMainWindow(0,0);
	QLabel* mainLabel = new QLabel("Main Widget Label", mainWindow);
	mainWindow->setCentralWidget(mainLabel);
	
	//This dock window should appear 50% transparent. Instead it is fully opaque.
	QDockWidget* dockWidget = new QDockWidget("Dock Widget", mainWindow);
	QPushButton* pushButton = new QPushButton("Dock Widget Button", dockWidget);	
	dockWidget->setWidget(pushButton);
	dockWidget->setWindowOpacity(0.5);
	mainWindow->addDockWidget(Qt::LeftDockWidgetArea, dockWidget); 

	//Just to show transparent can work, this seperate widget does show up 50% transparent.
	QWidget *w = new QWidget(0,0);
	QPushButton* floatingPushButton = new QPushButton("Floating Widget Button", w);
	w->setWindowOpacity(0.5);

	//Show the windows.
	mainWindow->show();
	w->show();

	return app.exec();
}

To copy to clipboard, switch view to plain text mode 

As you can see from the screenshot below, the regular QWidget is semi-transparent but the QDockWidget is not:



Is this expected? I guess it is conceivable that QDockWidgets are drawn differently (I notice they have different window decorations). Anyone know a way around this, or what I am doing wrong?

Thanks,

David