Merge pull request #7073 from gberaudo/notify_hidden_layer_group_changes

Make ol.layer.Group change handling consistent

src/ol/layer/group.js

@@ -80,9 +80,7 @@ ol.layer.Group.prototype.createRenderer = function(mapRenderer) {};
  * @private
  */
 ol.layer.Group.prototype.handleLayerChange_ = function() {
-  if (this.getVisible()) {
   this.changed();
-  }
 };