Hello,
Welcome to our forum and thank you for contacting us with your question!
To add a background to your stacked bar, the easiest way would be to add a fake series, with
grouping and
stacking disabled. Then, set a low
zIndex, disable
mouse tracking, set
showInLegend to false - and it's ready!
Take a look at the demo example to get a better understanding.
DEMO: https://jsfiddle.net/BlackLabel/oy6e0157/
In case of any other questions, feel free to contact us again,
Best regards!