diff --git a/externs/oli.js b/externs/oli.js
index 91ae1d9875..7f1d49940b 100644
--- a/externs/oli.js
+++ b/externs/oli.js
@@ -75,6 +75,23 @@ oli.MapBrowserEvent.prototype.pixel;
 
 
 
+/** @interface */
+oli.MapEvent;
+
+
+/**
+ * @type {ol.Map}
+ */
+oli.MapEvent.prototype.map;
+
+
+/**
+ * @type {olx.FrameState}
+ */
+oli.MapEvent.prototype.frameState;
+
+
+
 /**
  * @interface
  */
@@ -111,6 +128,7 @@ oli.interaction.DragAndDropEvent.prototype.projection;
 oli.interaction.DragAndDropEvent.prototype.file;
 
 
+
 /** @interface */
 oli.render.Event;
 
diff --git a/src/ol/mapevent.js b/src/ol/mapevent.js
index 4ac3bf4fd2..4eb7afaedb 100644
--- a/src/ol/mapevent.js
+++ b/src/ol/mapevent.js
@@ -27,6 +27,7 @@ ol.MapEventType = {
 /**
  * @constructor
  * @extends {goog.events.Event}
+ * @implements {oli.MapEvent}
  * @param {string} type Event type.
  * @param {ol.Map} map Map.
  * @param {?olx.FrameState=} opt_frameState Frame state.
@@ -36,12 +37,16 @@ ol.MapEvent = function(type, map, opt_frameState) {
   goog.base(this, type);
 
   /**
+   * The map where the event occurred.
    * @type {ol.Map}
+   * @todo api
    */
   this.map = map;
 
   /**
+   * The frame state at the time of the event.
    * @type {?olx.FrameState}
+   * @todo api
    */
   this.frameState = goog.isDef(opt_frameState) ? opt_frameState : null;
 
diff --git a/src/ol/source/vectorsource.js b/src/ol/source/vectorsource.js
index 03b4ffb3b6..b8e32af113 100644
--- a/src/ol/source/vectorsource.js
+++ b/src/ol/source/vectorsource.js
@@ -346,6 +346,7 @@ ol.source.Vector.prototype.getExtent = function() {
  *
  * @param {string|number} id Feature identifier.
  * @return {ol.Feature} The feature (or `null` if not found).
+ * @todo api
  */
 ol.source.Vector.prototype.getFeatureById = function(id) {
   var feature = this.idIndex_[id.toString()];