How to force scrollbar to show up in Streamlit?

I tried this style, but the scrollbar only shows up when I click on a button inside the container. Then when Streamlit reloads the page it's gone again. Any help appreciated.

st.markdown(""" <style> [data-testid="stVerticalBlockBorderWrapper"] > div:nth-child(1) { overflow-y: scroll !important; scrollbar-width: thin !important; /* Firefox support */ scrollbar-color: #888 #f1f1f1 !important; /* Firefox support */ } [data-testid="stVerticalBlockBorderWrapper"] > div:nth-child(1)::-webkit-scrollbar { width: 10px !important; display: block !important; } [data-testid="stVerticalBlockBorderWrapper"] > div:nth-child(1)::-webkit-scrollbar-track { background: #f1f1f1 !important; border-radius: 10px; } [data-testid="stVerticalBlockBorderWrapper"] > div:nth-child(1)::-webkit-scrollbar-thumb { background-color: #888 !important; border-radius: 10px; border: 2px solid #f1f1f1 !important; /* Creates a gap around the bar */ } </style>