Map widget missing layers when displayed more than once

[giswqs]

When rendering the map object multiple times in a Jupyter notebook, layers only show up the first time when it is displayed.

import ipywidgets as widgets

from maplibre import Layer, LayerType
from maplibre.sources import GeoJSONSource
from maplibre.controls import ScaleControl, Marker
from maplibre.ipywidget import MapWidget as Map

# Create a source
earthquakes = GeoJSONSource(
    data="https://docs.mapbox.com/mapbox-gl-js/assets/earthquakes.geojson"
)

# Create a layer
layer_id = "earthquakes"

earthquake_circles = Layer(
    type=LayerType.CIRCLE,
    id=layer_id,
    source=earthquakes,
    paint={"circle-color": "yellow"}
)

# Render map
m = Map(height="200px")
m.add_control(ScaleControl(), position="bottom-left")
m.add_layer(earthquake_circles)
m.add_tooltip(layer_id, "mag")
m.add_marker(Marker(lng_lat=(100.507, 13.745)))
m

[crazycapivara]

Yep, that's the expected behavior. After the map is rendered, the message queue is cleared!

[giswqs]

Is it possible to retain the message queue?

One use case is that users may want to see the map first before saving it to an HTML file. However, once the map is rendered, saving the map to an HTML file does not work properly anymore because the layers are gone.

[crazycapivara]

Yes, this seems to be a special use case for the ipywidget. We can store it This also makes it possible to get information about layers etc from the python object even after the map has rendered. So I will keep this issue open.