#include <QtGui>
#include <QtWidgets>

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

	auto w = new QDockWidget;
	auto button = new QLabel(QLatin1String("Some title"));
	w->setTitleBarWidget(button);

	w->resize(600,600);
	w->setAutoFillBackground(true);
	auto palette = w->palette();
	palette.setColor(QPalette::Background, QColor(0,0,0));
	w->setPalette(palette);

	w->show();
	app.exec();

	return 0;
}