diff --git a/lib/OpenLayers/Layer.js b/lib/OpenLayers/Layer.js
index 01178f086d..1366a2d95c 100644
--- a/lib/OpenLayers/Layer.js
+++ b/lib/OpenLayers/Layer.js
@@ -93,7 +93,11 @@ OpenLayers.Layer = OpenLayers.Class({
      * loadend - Triggered when layer loading ends.  When using a Vector layer
      *     with a Fixed or BBOX strategy, the event object includes a 
      *     *response* property holding an OpenLayers.Protocol.Response object.
-     * visibilitychanged - Triggered when layer visibility is changed.
+     * visibilitychanged - Triggered when the layer's visibility property is
+     *     changed, e.g. by turning the layer on or off in the layer switcher.
+     *     Note that the actual visibility of the layer can also change if it
+     *     gets out of range (see <calculateInRange>). If you want to catch
+     *     these cases, register for the map's 'changelayer' event instead.
      * move - Triggered when layer moves (triggered with every mousemove
      *     during a drag).
      * moveend - Triggered when layer is done moving, object passed as