Drilldown xAxis labels underline

[kamil-musialowski]

Actual behaviour

After drilling down on first xAxis category "Chrome", first three xAxis.labels are underlined.
This error occurs on chart.width < 430px.

Internal note

Possible regression, last working version 9.3.3.

Live demo with steps to reproduce

https://jsfiddle.net/BlackLabel/rwhp1cbj/
Click on "Chrome" and observe the first three labels after drilldown.

Product version

Highcharts 10.3.1
modules/drilldown 10.3.1

[hubertkozik]

A possible fix is to set more detailed xAxis.labels.style options:

xAxis: {
	labels: {
		style: {
			'text-decoration': 'none',
			'font-weight': 'normal'
		}
	}
  }

Demo with a workaround: https://jsfiddle.net/BlackLabel/897yxdjv/