QFontComboBox emits the currentFontChanged() signal twice

The output result should be 1 and font combo should have "Sans Serif" selected. Instead, output is 2 and font combo has some other font selected.

Code to reproduce:

//------------------------------------------------------------------------------------
#include <QtGui>
#include <QtTest>

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

QSignalSpy spy( & cb, SIGNAL( currentFontChanged( const QFont & ) ) );

QFont f( "Sans Serif" );
cb.setCurrentFont(f);

qDebug() << spy.count();

cb.show();
return app.exec();
}
//------------------------------------------------------------------------------------