QFileDialog with DontUseNativeDialog takes several minutes to show

#include <QApplication>
#include <QFileDialog>
#include <windows.h>

void MessageOutput( QtMsgType type, const QMessageLogContext &context, const QString &msg)
{
    QString message = "[DEBUG] -- " + msg + "\n";
    OutputDebugString(message.toStdString().c_str());
}

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

    QFileDialog dlg;
    dlg.setOption( QFileDialog::DontUseNativeDialog );
    dlg.show();    

    return app.exec();
}