diff --git a/src/ol/tile/tilegrid.js b/src/ol/tile/tilegrid.js
index 829c66ca21..e8d4c1c5ce 100644
--- a/src/ol/tile/tilegrid.js
+++ b/src/ol/tile/tilegrid.js
@@ -1,3 +1,5 @@
+// FIXME cope with tile grids whose minium zoom is not zero
+
 goog.provide('ol.TileGrid');
 
 goog.require('goog.array');