markers shared by multiple layers member of L.Control.Layers are disabled even if the remaining layers include them

In leaflet 0.3.1, when the same marker is added to more than one layer, all of which are added to L.Control.Layers as overlays, and one of the overlays is disabled, the marker is disabled.

e.g.

var groupA = new L.LayerGroup(),
    groupB = new L.LayerGroup();

map.addLayer(groupA).addLayer(groupB);

var overlays = {
 "A features": groupA,
 "B features": groupB,
};

map.addControl(new L.Control.Layers(null, overlays));

var marker = new L.Marker(new L.LatLng(1.0, 1.0));
groupA.addLayer(marker);
groupB.addLayer(marker);

Now, whenever the “A features” overlay is disabled, the marker is removed, even if the “B features” overlay is still enabled. Disabling and re-enabling “B features” does re-add the marker.

[rgeissert]

I wrote a workaround that does the trick for me. Perhaps this new behaviour should be hidden behind some forceReadd option or something, otherwise I might think its performance impact is not welcome.

[RinkAttendant6]

@MaxiPigna I think the workaround is in the cross-referenced commit here: https://github.com/rgeissert/Leaflet/commit/e273f1bb0aeef485d07c2814429a28ea9ea07474