Hacktoberfest 2026: the issues maintainers tagged for October, open and beginner-friendly. Browse Hacktoberfest issues

[BUG]: `axis.layer` / `axis.zerolinelayer`: `'above traces'` do not render above `scattergl` traces

Open
#8,075 0 comments 0 reactions 0 assignees View on GitHub

Maintainers usually reply within 1 day

Nobody has claimed this yet.

Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
55/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Active
Tech stack
javascript
Domain
data-visualization

Research direction

Start by running the linked CodePen reproductions and tracing how scattergl rendering interacts with the Cartesian axis and zeroline layer settings. Done means zerolinelayer: 'above traces' visibly places the zeroline above scattergl markers, while the documented behavior remains correct for the line-chart example.

Written by the indexing model from the issue text.

Description

bug
Description:

For Cartesian axes/subplots (for example, those containing scatter traces),
the reference documentation states that:

layer

Parent: layout.xaxis
Type: enumerated , one of ( "above traces" | "below traces" )
Default: "above traces"
Sets the layer on which this axis is displayed. If "above traces", this axis is displayed above all the subplot's traces If "below traces", this axis is displayed below all the subplot's traces, but above the grid lines. Useful when used together with scatter-like traces with cliponaxis set to "false" to show markers and/or text nodes above this axis.

zerolinelayer

Parent: layout.xaxis
Type: enumerated , one of ( "above traces" | "below traces" )
Default: "below traces"
Sets the layer on which this zeroline is displayed. If "above traces", this zeroline is displayed above all the subplot's traces If "below traces", this zeroline is displayed below all the subplot's traces, but above the grid lines. Limitation: "zerolinelayer" currently has no effect if the "zorder" property is set on any trace.

However, this does not work for scattergl.

A WebGL marker remains visually above the zeroline (y = 0) even when:

yaxis: {
  zerolinelayer: 'above traces'
}

is set.

Reproducible example:

https://codepen.io/Lexachoc/pen/xbqdWqm

https://codepen.io/Lexachoc/pen/EaWmLKY (line chart)

Relationship to cliponaxis:

This is separate from the feature request in #8074.

cliponaxis controls whether markers/text are clipped to the subplot's plotting area.

axis.layer / axis.zerolinelayer, on the other hand, control the stacking order of the axis / zeroline relative to traces.

Effect of axis.layer / axis.zerolinelayer: 'above traces':
Image

Effect of axis.layer / axis.zerolinelayer: 'above traces' for line chart (the red line should not be seen):

Image

Effect of cliponaxis: false:
Image

Dominant language
JavaScript
Stars
18.3k
Forks
2k
Avg merge
1d 19h
Merged PRs (30d)
21

Getting set up

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from plotly/plotly.js

All issues in plotly/plotly.js

Similar issues

More JavaScript issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.