Tooltips on scatter cannot be shown when there is a line behind it (breaks on version 5.0.8)(works on 5.0.7)

[tangyouze]

In highstock 5.0.7 when I create a figure with following series, I can see the tooltips on the scatter(black tooltips).

However this tooltip is missing when highstock upgrade to 5.0.8

        series: [{
            name: 'AAPL',
            data: data,
            zindex: 1,
            tooltip: {
                valueDecimals: 3
            }
        },
        {
            name: 'AAPL',
            type: 'scatter',
            zindex: 10,
            color: 'black',
            data: data,
            tooltip: {
                valueDecimals: 2
            }
        }
        
        ]

Jumping from highstock 5.0.7 to 5.0.8
The tooltips on scatter is missing(cannot be shown when mouse is around the node)

Expected behaviour

with version 5.0.7
http://jsfiddle.net/ao7zt82v/2/

Actual behaviour

with version 5.0.8
http://jsfiddle.net/92Lh0s5p/1/

Live demo with steps to reproduce

Affected browser(s)

Chrome, Edge, and may be more

[KacperMadej]

Thank you for reporting the problem.

This is more general - when tooltip has shared:true then it is not possible to displayed tooltip for any scatter point.
Simple demo: http://jsfiddle.net/jjt0a5z5/

[KacperMadej]

This commit seems (tested on issue-by-commit) to be causing the issue: fc77bfc

@jon-a-nygaard

[TorsteinHonsi]

Another case, scatter tooltip cannot be accessed: http://jsfiddle.net/highcharts/xgn6Lan4/5/