Updating chart type changes series order

[zimmemit]

Expected behaviour

Actual behaviour

In highstock with multiple series, when the series type is updated, it changes the order that series are appearing in. In the example, the blue line starts furthest back after updating, it moves to the front.

Am I doing something terribly wrong with updating the series type and/or is this the expected behavior?

Live demo with steps to reproduce

https://jsfiddle.net/zimm56/nhcn8f5b/

Affected browser(s)

Non browser specific

[pawelfus]

Hi @zimmemit

Thank you for reporting this issue.

Workaround:
Define series.zIndex when initializing series: https://jsfiddle.net/nhcn8f5b/4/

Internal note:
It used to work with 2.0.4 (2010), but issue-by-commit doesn't load that old versions.

[TorsteinHonsi]

Related: #6112

[TorsteinHonsi]

Minimal demo: https://jsfiddle.net/highcharts/nhcn8f5b/5/

It also happens in basic Highcharts.

[TorsteinHonsi]

It happened because we destroy the groups when updating series type, and re-create them without a Z index, which means they were appended to the end. I can see no reason why to destroy the groups when we only have to update the Z index if the zIndex option change. So I refactored this.