Toggling a line from the legend through the keyboard in high contrast mode does not work

[FrankTaubert]

Expected behaviour

In High contrast mode: It should be possible to un-select a line in a line chart by pressing space bar when the name is selected in the legend next to the chart.

Actual behaviour

The line is not hidden. Clicking on the label works.

Looking at the code: it seems the keydown event is register twice and leads to the line being hidden and immediately being shown again.

This happens in KeyboardNavigation.prototype.init = function (chart, components) (accessibility.src.js).
Wher in Accessibility.prototype.init = function (chart) {

1. this.keyboardNavigation = new KeyboardNavigation(chart, this.components); registers a key down event (number 1)
2. the next line is this.update();
3. which calls setHighContrastTheme
4. which triggers an update of the series
5. which updates of the chart and updateA11yEnabled
6. which leads to the creation of a new Accessibility(
7. which leads to the creation of a new KeyboardNavigation
8. which registers a key down event (number 2)
9. it will not register another one, as step 3) setHighContrastTheme is not called again, as highContrastModeActive is true at this point.

Live demo with steps to reproduce

https://jsfiddle.net/gh/get/library/pure/highcharts/highcharts/tree/master/samples/highcharts/demo/line-basic
The issue is visible when I turn on the Windows high contrast mode and open the above jsfiddle in the browser
Steps:

• in high contrast mode
• navigate to "installation" in the legend on the right side of the graph
• press "space"
• "installation" line stays visible / is not deactivated
• click on the same label
• "installation" line disappears / is deactivated

Product version

v9.3.0 (2021-10-21)

Affected browser(s)

Edge Version 95.0.1020.30 (Official build) (64-bit)

[raf18seb]

Hi @FrankTaubert, thanks for reporting the issue and describing it well.

[FrankTaubert]

Hi @raf18seb, I wanted to ask if you have an estimate on if you are going to fix this and how long it will take? This was flagged as severity 1 bug by the accessibility team of my organisation. So it's urgent for us, that this gets fixed.

[raf18seb]

Hi @FrankTaubert, we'll look into this issue this week and provide more info soon.

[oysteinmoseng]

@FrankTaubert A PR with the fix is under review, and you can expect this issue to be resolved in the next Highcharts release. Thank you for providing such great detail and investigative work in the bug report!

[FrankTaubert]

Hi @oysteinmoseng, is there a target date to that release?