diff --git a/lib/OpenLayers/Control/PinchZoom.js b/lib/OpenLayers/Control/PinchZoom.js
index e89fa287f6..f55d08e9fc 100644
--- a/lib/OpenLayers/Control/PinchZoom.js
+++ b/lib/OpenLayers/Control/PinchZoom.js
@@ -43,7 +43,12 @@ OpenLayers.Control.PinchZoom = OpenLayers.Class(OpenLayers.Control, {
 
     /**
      * APIProperty: preserveCenter
-     * {Boolean} Force the map center to stay in place. Default is false.
+     * {Boolean} Set this to true if you don't want the map center to change
+     *     while pinching. For example you may want to set preserveCenter to
+     *     true when the user location is being watched and you want to preserve
+     *     the user location at the center of the map even if he zooms in or
+     *     out using pinch. This property's value can be changed any time on an
+     *     existing instance. Default is false.
      */
     preserveCenter: false,