Unregister the window when unloaded.

chrome/content/openspace.js

@@ -1,11 +1,10 @@
 
-// TODO: when to unregister this window?
-
 var openspace = {
 
     /**
      * Loads some modules and populates the listbox with spaces known
-     * in the space directory.
+     * in the space directory. After the initialization this object
+     * is registered as an observer in the OpenSpace javascript module.
      */
     onLoad: function() {
 
@@ -45,6 +44,13 @@ var openspace = {
         this.initialized = true;
     },
 
+    /**
+     * Unregisters this object as an observer in the OpenSpace javascript module.
+     */
+    onUnLoad: function(){
+        unregisterOpenSpaceObserver(this);
+    },
+
     /**
      * Displays a green, red or a grey dot. The colors have the following meaning:
      *
@@ -147,4 +153,5 @@ var openspace = {
     }
 };
 
-window.addEventListener("load", function(e) { openspace.onLoad(e); }, false);
+window.addEventListener("load", function(e) { openspace.onLoad(e); }, false);
+window.addEventListener("unload", function(e){ openspace.onUnLoad(e); }, false);