Checklist

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• I have provided sufficient information below to help reproduce this issue.

Summary

Streamlit multi_select element st.multi_select not working as expected inside streamlit form st.form. After selecting multiple options through the multi select element, on form submission, the multiselect widget giving empty value [].

Reproducible Code Example

import streamlit as st

with st.form(key="async_testing_config"):
        # Components : Select async api endpoints for testing.
        components = st.multiselect(
            "Select async api endpoints",
           external_call_to_aws_api_to_get_list_of_endpoints(),
            key="components"
        )

        # Submitted - BOOLEAN
        Submitted = st.form_submit_button("Submit")
        if Submitted:
            print("project id: ", project_id)
            print("endpoints: ",components)

Steps To Reproduce

No response

Expected Behavior

After submitting the form, user should be able to get all options selected through multi select widget.

Current Behavior

User getting empty value after submitting. Note: the options passed to the multiselect widget is an external api call to aws api to list of endpoints (options). I tried with streamlit version 1.28.2 and also latest version 1.29.0 as well, facing the same issue.

Is this a regression?

• Yes, this used to work in a previous version.

Debug info

• Streamlit version: 1.28.2
• Python version: 3.9
• Operating System: Mac
• Browser: Chrome

Additional Information

No response