Highchart setNegativeColor has no effect

Hello everyone,

I want to write a special behavior for negative parts of an AREASPLINE chart.
I read setNegativeColor can set a css class, .highcharts-negative, for negative parts.
Sounds great but it does not work.

I tried on

  • Vaadin 14 (setNegativeColor true on PlotOptionsAreaspline)
  • Vaadin 24 (setNegativeColor SolidColor.RED on PlotOptionsAreaspline)
    • is there anyway to just activate the class writing instead of forcing a color?

Does anyone have a clue please?