WIP on map-link:

- fix bug in first added or removed map-feature

src/mapml/layers/FeatureLayer.js

@@ -118,10 +118,13 @@ export var FeatureLayer = L.FeatureGroup.extend({
     // static FeatureLayer (e.g. MapMLLayer._mapmlvectors) NEVER has a
     // .layerBounds property, so if there is this.options.layerBounds, don't
     // go copying it to this.layerBounds.  Same for zoomBounds.
+    // bug alert: it's necessary to create a new bounds object to initialize
+    // this.layerBounds, to avoid changing the layerBounds of the first geometry
+    // added to this layer
     if (!this.options.layerBounds) {
       this.layerBounds = this.layerBounds
         ? this.layerBounds.extend(layerToAdd.layerBounds)
-        : layerToAdd.layerBounds;
+        : L.bounds(layerToAdd.layerBounds.min, layerToAdd.layerBounds.max);
 
       if (this.zoomBounds) {
         if (layerToAdd.zoomBounds.minZoom < this.zoomBounds.minZoom)
@@ -178,12 +181,15 @@ export var FeatureLayer = L.FeatureGroup.extend({
       let layerIds = Object.keys(this._layers);
       // re-calculate the layerBounds and zoomBounds for the whole layer when
       // a feature is permanently removed from the overall layer
+      // bug alert: it's necessary to create a new bounds object to initialize
+      // this.layerBounds, to avoid changing the layerBounds of the first geometry
+      // added to this layer
       for (let id of layerIds) {
         let layer = this._layers[id];
         if (layerBounds) {
           layerBounds.extend(layer.layerBounds);
         } else {
-          layerBounds = layer.layerBounds;
+          layerBounds = L.bounds(layer.layerBounds.min, layer.layerBounds.max);
         }
         if (zoomBounds) {
           if (layer.zoomBounds.minZoom < zoomBounds.minZoom)