Highcharts marker layering - how to configure overlapping of multiple series

Use case

In a multi series HTML5 chart (aka combination chart) you sometimes want to have control over which markers appear on top. In one particular scenario user had a Bar+Scatter combination chart. The scatter markers were drawn behind the bars when overlapped, and we needed to have the scatter points displayed on top. 

Solution

The layer controls is achievable using Highcharts property called zIndex: 

https://api.highcharts.com/highcharts/series.bar.zIndex 

You will have to assign a zIndex property to each or your chart Measures as a SeriesProperty. Like this: 

The higher the value of the zIndex, the closer your Measure is to the top. By default the Measures are displayed in order of declaration.