Highlighting of points disappears when updating yAxis on mouseover event over point in chart

[marek-aguita]

Expected behaviour

Highlighting of points works exactly the same way as without any yAxis modification.

Actual behaviour

Highlighting of points somehow disappears when attempting to change some styles of an yAxis and hovering over a point in such modified chart. It looks like it is there for a millisecond, but then it's gone.

Live demo with steps to reproduce

https://jsfiddle.net/8k1zqd3x/27/
First chart in the demo contains yAxis.update call with some styling modifications. There is no permanent highlight in this scenario, as per this picture:

Second chart has yAxis.update code commented out, the highlight feature works properly:

Product version

Highcharts 7.2.1

Affected browser(s)

all

[pawelfus]

Thanks for reporting this issue @vodess

Bisected to commit 5e23ec2

FYI @jon-a-nygaard

[pawelfus]

Internal note:
Most likely issue comes from these lines: 5e23ec2#diff-6a484c602b63f88ee9f97efd254ee22fR299-R303

Perhaps, when hoverPoint is the same, we don't need to fire these events.

[sebastianbochan]

Internal note
After deep debugging it looks like more complex issue, because of two problems here:

1. The setState is always triggered with "move" param, which causes the issue with halo.
   

   highcharts/ts/parts/Pointer.ts

   Line 1837 in 1ae472d

   hoverPoint.setState(hoverPoint.state, true);

Its related with commit e3f4302 and bug #2500

Its a regression, but Im not sure how to detect the "move". My idea is to check the extremes on axis, but it sounds as workaround, not solution.

2. When we trigger:
   2.1 setState('hover')
   2.2 axis.update({});

   Demo:
   - http://jsfiddle.net/BlackLabel/jvkw8m93/

   Then hover marker is lost.

@TorsteinHonsi any ideas?

[TorsteinHonsi]

No... I guess we need to go to the offending commits and see why it now fails. Checking the extremes of the axis indeed seems like a workaround - we should have to add new conditions, just find out what made it work earlier, and why that was lost.