Stylesheet: the disabled pseudo-state is not available for QPushbutton

It seems that the disabled pseudo state is not available for QPushButton

Example:

#include <QtGui>

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

QWidget myWidget;

QVBoxLayout *layout = new QVBoxLayout;
QPushButton *push1 = new QPushButton("underline");
push1->setStyleSheet("QPushButton:disabled

");
push1->setDisabled(true);
QPushButton *push2 = new QPushButton("line-through");
push2->setStyleSheet("QPushButton

");
layout->addWidget(push1);
layout->addWidget(push2);
myWidget.setLayout(layout);

myWidget.show();

return app.exec();
}