Hi,
If we set chart's height percentage then chart's aspect ratio remain same while shrinking or widening chat/window's width. But after calling Chart.update() the chart doesn't respond to width change anymore. Also noticed this happens only if the chart's axis length (xAxis.max) is changed by update(). Here is the issue reproduced -
https://jsfiddle.net/hasanahmed/5bkaL7wp/92/