Popup disappears after click in demo environment

[Lux-CC]

In the "dynamic updates" example, clicking a marker shows a popup. But the moment the page is rerendered after about 1 second, the popups disappear (using chrome at least).

Is this intended behavior? If it isn't I'm willing to try and figure out the problem and submit a PR, but if you can nudge me in the right direction that would be great!

Thanks for your work on this package!

Link to page I'm talking about:
https://folium.streamlit.app/dynamic_updates

[hansthen]

This will be difficult to fix, especially when patching only It is probably sufficient to streamlit-folium. The reason is that st_folium rerenders the layers in feature_group_to_add on each update.

You can probably do this in user code, but it will require adding some event handlers. I will provide links to javascript examples, which you will need to translate into folium.JsCode. You can see examples how this is done here: https://python-visualization.github.io/folium/latest/user_guide/plugins/realtime.html and here: https://python-visualization.github.io/folium/latest/reference.html#folium.map.Evented

1. You need to catch the popup open event.
   https://stackoverflow.com/questions/12701240/how-to-identify-leaflets-marker-during-a-popupopen-event

2. In the event handler you need to store the data that is needed to recreate the popup in Window.sessionStorage. See https://developer.mozilla.org/en-US/docs/Web/API/Window/sessionStorage for more details.

3. In the map load event, you need to ensure that any popup data is pre-opened.
   See https://leafletjs.com/reference.html#popup for examples.