diff --git a/src/ol/animation.js b/src/ol/animation.js
index 3c40d2ddc6..6b80f0accc 100644
--- a/src/ol/animation.js
+++ b/src/ol/animation.js
@@ -1,3 +1,5 @@
+// FIXME works for View2D only
+
 goog.provide('ol.animation');
 
 goog.require('goog.fx.easing');
diff --git a/src/ol/framestate.js b/src/ol/framestate.js
index ccb38ccdc3..032dac1ed7 100644
--- a/src/ol/framestate.js
+++ b/src/ol/framestate.js
@@ -1,3 +1,5 @@
+// FIXME add view3DState
+
 goog.provide('ol.FrameState');
 goog.provide('ol.PostRenderFunction');
 goog.provide('ol.PreRenderFunction');
diff --git a/src/ol/map.js b/src/ol/map.js
index 8b623c8320..01a180637c 100644
--- a/src/ol/map.js
+++ b/src/ol/map.js
@@ -585,6 +585,7 @@ ol.Map.prototype.renderFrame_ = function(time) {
       this);
 
   if (!goog.isNull(frameState)) {
+    // FIXME works for View2D only
     var center = view2DState.center;
     var resolution = view2DState.resolution;
     var rotation = view2DState.rotation;