Stylesheet bug - :read-only has no effect

Opposite to [readOnly="true"] which works flawlessly, :read-only does not work.

Code to reproduce:
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#include <QtGui>

int main( int argc, char * argv[] )
{
QApplication app( argc, argv );
QMainWindow mainWindow;
QWidget * centralWidget = new QWidget( & mainWindow );
mainWindow.setCentralWidget( centralWidget );
QHBoxLayout * layout = new QHBoxLayout;
centralWidget->setLayout( layout );

QPlainTextEdit * edit1 = new QPlainTextEdit( centralWidget );
layout->addWidget( edit1 );

QPlainTextEdit * edit2 = new QPlainTextEdit( centralWidget );
edit2->setReadOnly( true );
layout->addWidget( edit2 );

QString s = "QPlainTextEdit

{ background-color: blue; }

"
// WORKS
//"QPlainTextEdit[readOnly=\"true\"]

{ background-color: red; }

";
// DOES NOT WORK
"QPlainTextEdit:read-only

{ background-color: red; }

";
app.setStyleSheet( s );

mainWindow.show();
return app.exec();
}
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