QLineSeries + black color

[fem_dev]

I have a proble with just one single color when I try to color the QLineSeries object:

// Create a series:
QLineSeries *serie = new QLineSeries(chart);

// It works! I got a yellow line!
serie->setColor(Qt::yellow);

// The black color doesn't work! Why?
serie->setColor(Qt::black);

When I try to use the black color, I got default series color (which is Qt::color1 - Blue)

In this link you can see the Qt Named Colors.

Why Qt::black doesn't work?