diff --git a/src/ol/source/vectorsource.js b/src/ol/source/vectorsource.js
index 736d3f7e0a..cf8fe4660c 100644
--- a/src/ol/source/vectorsource.js
+++ b/src/ol/source/vectorsource.js
@@ -1,6 +1,8 @@
+// FIXME bulk feature upload - suppress events
 // FIXME put features in an ol.Collection
 // FIXME make change-detection more refined (notably, geometry hint)
 // FIXME keep R-Tree up-to-date, probably needs a new R-Tree implementation
+// FIXME iterate over R-Treed, needs a new R-Tree implementation
 
 goog.provide('ol.source.Vector');