FeatureGroups named using numeric string always placed first in LayerControl

[JuliusGoelz]

Describe the bug Adding multiple FeatureGroups to a LayerControl where some are named using a numerical string causes those groups to always come first in the layer control on the map, even though feature groups named using alphanumeric strings are unsorted and sortLayers argument is set to False.

Screenshot:

I have not managed to find any documentation saying that this is intended behaviour.

To Reproduce

import folium

m = folium.Map(location=[0, 0], zoom_start=6)

fg1 = folium.FeatureGroup("z")
m.add_child(fg1)

fg2 = folium.FeatureGroup("a")
m.add_child(fg2)

fg3 = folium.FeatureGroup("2a")
m.add_child(fg3)

fg4 = folium.FeatureGroup("1")
m.add_child(fg4)

folium.Marker([-1, -1]).add_to(fg1)
folium.Marker([1, 1]).add_to(fg2)
folium.Marker([-1, 1]).add_to(fg3)
folium.Marker([1, -1]).add_to(fg4)

folium.LayerControl(collapsed=False, sortLayers=False).add_to(m)

m

Expected behavior FeatureGroups appearing in the LayerControl in the order they were added to the map when sortLayers argument is set to False.

In the case of the example: z -> a -> 2a -> 1

Environment (please complete the following information):

• Jupyter Notebook
• Python version: 3.12.6
• folium version 0.18.0

Additional context

--

Possible solutions

• Inserting a space/any other symbol after the number makes it appear where I would expect it to
• I tried supplying a js sortFunction to LayerControl as a string, but it resulted in the layer control not showing up. Is this not supposed to be used in Python?