[BUG] AgGrid not displaying data under st.expander

[johannesocean]

Describe the bug
Since Streamlit 1.43.0 I can no longer see my AgGrid under an st.expander on initial load. However, if I right-click and press "refresh frame" the data pops up.

To Reproduce

streamlit == 1.55.0
streamlit-aggrid== 1.2.1.post2

import streamlit as st
from st_aggrid import AgGrid
import pandas as pd

df = pd.read_csv('https://raw.githubusercontent.com/fivethirtyeight/data/master/airline-safety/airline-safety.csv')

with st.expander("Data", expanded=False):
    AgGrid(df, key="airline_grid")

---

Behavior

Screenshare.-.2026-03-16.7_57_12.AM.mp4

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Expected behavior
With streamlit==1.42.0

Screenshare.-.2026-03-16.7_55_34.AM.mp4

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Any suggestions?

[johannesocean]

a somewhat cumbersome solution below (that I do not like). There has to be a better way...

expander_key = "expander_open"

if expander_key not in st.session_state:
    st.session_state[expander_key] = False

def on_expander_change(key: str):
    st.session_state[key] = not st.session_state[key]

with st.expander("About", expanded=False, on_change=lambda: on_expander_change(expander_key)):
    grid_container = st.container()
    if st.session_state[expander_key]:
        with grid_container:
            AgGrid(df)

[johannesocean]

Any thoughts on this @PablocFonseca ? :)