Sidebar permanently hidden; cannot be display

Using Streamlit
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Welcome to the community, and thanks for the detailed question! :blush: If your sidebar disappeared after clicking the hide/collapse arrow and won’t reappear—even after using st.set_page_config(initial_sidebar_state=“expanded”) and clearing cache—it’s likely due to a persistent user setting in your browser’s local storage, not your code. Streamlit remembers the sidebar state per user, so once you collapse it, it stays collapsed until you manually expand it again using the sidebar’s toggle arrow. If the arrow is missing, this could be due to custom CSS or a browser rendering issue.

To restore the sidebar, ensure you haven’t hidden the toggle arrow with CSS (e.g., targeting [data-testid=“collapsedControl”]). If you have, remove or adjust that CSS. If the arrow is still missing, try a different browser or clear your browser’s local storage for localhost. For alternative layouts, Streamlit’s st.columns allows you to place content on the sides, but true sidebars with toggle functionality are only available via st.sidebar. For more, see the Streamlit sidebar docs.

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