See: https://discuss.streamlit.io/t/is-there-a-way-to-specify-column-width-for-dataframe-table/333

st.dataframe tries to be smart about column sizes, but often misses the mark — so users end up with dataframes that have truncated/ellipsized values.

On Jupyter, you can apply a width-modifying Styler to a dataframe like this: https://stackoverflow.com/a/39680725

We should add support for something like that in Streamlit.