Is it possible to add a background color or highlight to the value labels? I'm trying to apply this to the value labels on an area chart, and my problem is that the labels sometimes overlap with the dark colors of the area chart. I can't just make the value label's font color white, because then the parts of the labels that aren't overlapping the area chart would be invisible against the white background. I can try and set it to a middle grey color, but then they won't stand out very well against either the area chart's colors or the background.
Ideally I could just set some sort of background color or highlight to the value label, this way the values are always visible no matter what's behind them. I tried adding "backgroundColor" and "borderColor" to the style tag, but that didn't seem to work.
