On_selection event in faceted plot only works correctly in first facet

📊 Plotly Python
1

Hello,
I’m trying to catch on_selection events in a faceted figure.

I create a simple faceted figure, and attach an on_selection handler to all traces.
As an output, I simply print the customdata, and the selector.xrange.

When selecting an area in the first facet, the selector.xrange is an array of numbers, the customdata corresponds to the data for the left facet.
However, when I do the same in the second facet, the selector.xrange becomes an , and the customdata still appears to be coming from the left facet.

I expect the selector.xrange to also be an array of numbers, when selecting in the right facet.

Here are the sample code (to be executed in jupyter notebook) and a screenshot of the result.

import plotly.graph_objs as go
import plotly.express as px
import plotly.offline as py

import pandas as pd
import numpy as np
from ipywidgets import interactive, HBox, VBox

py.init_notebook_mode()

df = pd.DataFrame({
    "x": [1,2,3,4,1,2,3,4],
    "y": [1,2,3,2,1,4,2,3],
    "side": ["left","left","left","left","right","right","right","right"],
    "customdata": [1,2,3,4,5,6,7,8]
})

fig = px.line(df, x="x", y="y", custom_data=["side","customdata"], facet_col="side")

# fig.update_layout(clickmode='event+select')
fig.update_layout(
            dragmode="select",
            clickmode="select"
        )
fig.update_traces(marker_size=20)

f = go.FigureWidget(fig)

def click_handler(trace, points, selector):
    print(trace.customdata)
    print(selector.xrange)
    
f.data[0].on_selection(click_handler)

f

image
image900×562 21.7 KB

Is this a configuration issue or a bug ?

Thank you

Bart