diff --git a/lib/OpenLayers/Popup.js b/lib/OpenLayers/Popup.js
index 44fc3c2754..2b9c536273 100644
--- a/lib/OpenLayers/Popup.js
+++ b/lib/OpenLayers/Popup.js
@@ -37,6 +37,9 @@ OpenLayers.Popup.prototype = {
     /** @type String */
     border: "",
 
+    /** this gets set in Map.js when the popup is added to the map
+     * @type OpenLayers.Map */
+    map: null,
 
     /** 
     * @constructor
@@ -66,6 +69,7 @@ OpenLayers.Popup.prototype = {
             this.div.parentNode.removeChild(this.div);
         }
         this.div = null;
+        this.map = null;
     },
 
     /**