Properly detect feature on unmanaged layer for toggle selection

src/ol/source/vectorsource.js

@@ -739,6 +739,16 @@ ol.source.Vector.prototype.handleFeatureChange_ = function(event) {
 };
 
 
+/**
+ * @param {ol.Feature} feature Feature.
+ * @return {boolean} Feature is in source.
+ */
+ol.source.Vector.prototype.hasFeature = function(feature) {
+  var id = feature.getId();
+  return id ? id in this.idIndex_ : goog.getUid(feature) in this.undefIdIndex_;
+};
+
+
 /**
  * @return {boolean} Is empty.
  */