set QProgressDialog. progress indicator color?

[steps]

Carlos, I tried what you suggested in a class that is derived from QProgressBar. This is my code:

void MyProgressBar::onStarted()
{
    setFormat(tr("Preparing"));
 
    QPalette p = this->palette();
    QBrush greenBrush(QColor(0, 255, 0, 255));
    greenBrush.setStyle(Qt::SolidPattern);
    p.setBrush(QPalette::Active, QPalette::Highlight, greenBrush);
    p.setBrush(QPalette::Inactive, QPalette::Highlight, greenBrush);
    this->setPalette(p);
}

void MyProgressBar::onStarted()
{
    setFormat(tr("Preparing"));

    QPalette p = this->palette();
    QBrush greenBrush(QColor(0, 255, 0, 255));
    greenBrush.setStyle(Qt::SolidPattern);
    p.setBrush(QPalette::Active, QPalette::Highlight, greenBrush);
    p.setBrush(QPalette::Inactive, QPalette::Highlight, greenBrush);
    this->setPalette(p);
}

To copy to clipboard, switch view to plain text mode 

But the color doesn't change. Maybe you can spot my mistake?