Multiple traces in a FigureWidget break callbacks

[hgfoisu59fj]

Hello!
I am using

plotly 5.7.0
jupyterlab 3.3.2
ipywidgets 7.7.0
(these are the latest versions of each package)

I am not using Dash.
What I am trying to achieve is a simple FigureWidget with two scatter plots in it, each with a callback that prints the element the user has clicked on. However, the callbacks are fired incorrectly. The trace object given to the callback function is always the last added trace, not the one that the user clicked on.

Here is a minimal example which I adapted from the official documentation (plotly.com/python/click-events/#update-points-using-a-click-callback)

import plotly.graph_objects as go
from ipywidgets import Output
import numpy as np
import ipywidgets

np.random.seed(1)

scatter_1 = go.Scatter(x=np.random.rand(100), y=np.random.rand(100), mode='markers', hovertext="hello, I am scatter 1", marker={"symbol": "triangle-up", "size": 10, "color": "red"},)
scatter_2 = go.Scatter(x=np.random.rand(100), y=np.random.rand(100), mode='markers', hovertext="hello, I am scatter 2", marker={"symbol": "triangle-down", "size": 10, "color": "blue"},)

f = go.FigureWidget()
f.add_trace(scatter_1)
f.add_trace(scatter_2)
f.layout.hovermode = 'closest'

f

This correctly renders the figure:

Then, I add a callback, one to each trace, by manipulating f.data :

o = ipywidgets.Output()

@o.capture(clear_output=True)  
def callback(trace, points, selector):
    print(trace)
    print(points)
    print(selector)
        
f.data[0].on_click(callback)
f.data[1].on_click(callback)

o

Clicking a blue triangle works, it correctly shows the clicked trace and point:

Clicking a red triangle yields wrong output. The point object is somehow empty, and the trace object is wrong (trace 1 even though trace 0 was clicked):

Is there something obvious I’m doing wrong, or is it a very unusual use case I have with two traces in a FigureWidget that nobody has run into this?