google combo chart move area to the back

[Linda van Engelen]

We have a google combo chart with 5 areas and 1 bar.

The horizontal lines als Areas, because we needed 5 different colored lines.

But whatever we try, the area lines are displayed over the bar. I tried to put the series in a different order. Like first the bar serie and than the area series, or reversed.

Does anyone know how you can force to put the area series to the back, so the bar is more visible?