Multiple y axes -> only one scatter shows up

Issue

When plotting data on multiple Y axes, particularly when nothing is plotted on the primary Y axis, sometimes plotly will only show one series.

Repro

https://codepen.io/jasoncurtis/pen/zmqNMQ?editors=0010

Expected behavior

Two series are plotted.

Actual behavior

Two series show up in the legend, but only one series is plotted.

Workaround

If you change 'y2' in the repro code above to ‘y1’, both series will show up. However, it’s not always reasonable to assume there will be data on y1 - I am trying to write a purpose-specific API that uses plotly in such a way that I cannot guarantee there will be something on y1 without significant extra complexity.

Related:

• I filed plotly/plotly.py#1200 for this and was referred here since this is a plotly.js issue.
• it appears that this issue may have been the source of #1970 which was closed because @alexmon’s repro did not work.

[alexcjohnson]

If you want to ensure yaxis is always drawn, put a dummy invisible trace on it, like {visible: false} (which will implicitly be drawn on xaxis and yaxis). If you don’t want to see yaxis, just have it there to be overlaid on, you can make it too visible: false https://codepen.io/alexcjohnson/pen/oazbvv?editors=0010

[Tunneller]

This discussion was incredibly useful to help me debug why I was not getting curves on my plots. You mean that ‘overlapping: “y”’ is not short-hand for ‘overlapping: “yes”’… I spent 24 sleep deprived hours on this. Now that I’ve got it all working, everything makes sense. And that solution was to simply insert {visible: false}. Wow. So neat. Er… is this in the documentation yet?