Width of Altair vconcat chart not correct

Summary

I am trying to implement multiple concatenated charts with same x-axis to share a selection functionality. When adding them to streamlit one at a time, the width seems to adjust to the container automatically, but something goes wrong when adding the concatenated charts.

Steps to reproduce

Code snippet:

import pandas as pd
import numpy as np
import altair as alt
import streamlit as st

st.set_page_config( layout='wide')

x = np.linspace(10,100, 10)
y1 = 5*x
y2 = 1/x

df1 = pd.DataFrame.from_dict({'x': x,'y1': y1, 'y2': y2})

c1 = alt.Chart(df1).mark_line(
).encode(
    alt.X('x'),
    alt.Y('y1')
)

c2 = alt.Chart(df1).mark_line(
).encode(
    alt.X('x'),
    alt.Y('y2')
)

#Individual, Static Charts
st.altair_chart(c1, use_container_width = True)
st.altair_chart(c2, use_container_width = True)

#Concatenated Charts with shared zoom function
zoom = alt.selection_interval(bind = 'scales', encodings = ['x'])
st.altair_chart(c1.add_selection(zoom) & c2.add_selection(zoom), use_container_width = True)

Expected behavior:

Concatenated charts of full width with zoom functionality.

Actual behavior:

Concatenated charts of standard width with zoom functionality

Is this a regression?

No.

Debug info

• Streamlit version: 0.76.0
• Python version: 3.8.5
• Using PipEnv
• OS version: macOS Mojave
• Browser version: Chrome

Additional information

[quantoid]

Hi, any update on this, like a target release date?

[StefanRinger]

Would also be happy about a fix