Set new added layers as active

src/style_manager/model/Layers.js

@@ -12,6 +12,7 @@ export default Backbone.Collection.extend({
 
   onAdd(model, c, opts) {
     if (!opts.noIncrement) model.set('index', this.idx++);
+    opts.active && this.active(this.indexOf(model));
   },
 
   onReset() {

src/style_manager/view/PropertyStackView.js

@@ -70,7 +70,7 @@ export default PropertyCompositeView.extend({
     const layers = this.getLayers();
     const properties = model.get('properties').deepClone();
     properties.each(property => property.set('value', ''));
-    const layer = layers.add({ properties });
+    const layer = layers.add({ properties }, { active: 1 });
 
     // In detached mode inputValueChanged will add new 'layer value'
     // to all subprops