Re-render selectbox after session_state change

Hey, streamlit community!

Currently, I am facing a problem, that my selectbox is not re-rendered even though the index value changes.

I have a button that changes the session state with the key date_index. After pressing the button and increasing this state, I would expect my date selectbox to rerender. But it does not.

Here a code snippet:

date = st.selectbox('Select a day', dates, format_func=day_name, key='date',
                            index=st.session_state['date_index'], on_change=update_date_index, args=(dates, ))

As you can see, I am using the key date_index in the session state. Is there a hack or an official that allows the re-render after the index value changes?

Thank you!