[Solved]-Highcharts - Format overlapping scatter points in a shared tooltip-Highcharts

Shared tooltip does not work with scatter series - please check this issue: https://github.com/highcharts/highcharts/issues/1431

The simplest solution is to use line series type with lineWidth property set to 0:

plotOptions: {
    series: {
        lineWidth: 0,
        states: {
            hover: {
                lineWidthPlus: 0
            }
        }
    }
},

Live demo: http://jsfiddle.net/BlackLabel/3fda1nm4/

API Reference: https://api.highcharts.com/highcharts/series.line.lineWidth