--- a/suite/common/places/src/nsPlacesAutoComplete.js
+++ b/suite/common/places/src/nsPlacesAutoComplete.js
@@ -347,16 +347,19 @@ function nsPlacesAutoComplete()
       "ORDER BY IFNULL(h_t.frecency, h.frecency) DESC"
     );
   });
 
   //////////////////////////////////////////////////////////////////////////////
   //// Initialization
 
   // load preferences
+  this._prefs = Cc["@mozilla.org/preferences-service;1"].
+                getService(Ci.nsIPrefService).
+                getBranch(kBrowserUrlbarBranch);
   this._loadPrefs(true);
 
   // register observers
   this._os = Cc["@mozilla.org/observer-service;1"].
               getService(Ci.nsIObserverService);
   this._os.addObserver(this, kQuitApplication, false);
 
 }
@@ -493,21 +496,18 @@ nsPlacesAutoComplete.prototype = {
   //// nsIObserver
 
   observe: function PAC_observe(aSubject, aTopic, aData)
   {
     if (aTopic == kQuitApplication) {
       this._os.removeObserver(this, kQuitApplication);
 
       // Remove our preference observer.
-      let prefs = Cc["@mozilla.org/preferences-service;1"].
-                  getService(Ci.nsIPrefService).
-                  getBranch(kBrowserUrlbarBranch).
-                  QueryInterface(Ci.nsIPrefBranch2);
-      prefs.removeObserver("", this);
+      this._prefs.removeObserver("", this);
+      delete this._prefs;
 
       // Finalize the statements that we have used.
       let stmts = [
         "_defaultQuery",
         "_historyQuery",
         "_bookmarkQuery",
         "_tagsQuery",
         "_typedQuery",
@@ -638,32 +638,30 @@ nsPlacesAutoComplete.prototype = {
    * Loads the preferences that we care about.
    *
    * @param [optional] aRegisterObserver
    *        Indicates if the preference observer should be added or not.  The
    *        default value is false.
    */
   _loadPrefs: function PAC_loadPrefs(aRegisterObserver)
   {
-    let prefs = Cc["@mozilla.org/preferences-service;1"].
-                getService(Ci.nsIPrefService).
-                getBranch(kBrowserUrlbarBranch);
+    let self = this;
     function safeGetter(aName, aDefault) {
       let types = {
         boolean: "Bool",
         number: "Int",
         string: "Char"
       };
       let type = types[typeof(aDefault)];
       if (!type)
         throw "Unknown type!";
 
       // If the pref isn't set, we want to use the default.
       try {
-        return prefs["get" + type + "Pref"](aName);
+        return self._prefs["get" + type + "Pref"](aName);
       }
       catch (e) {
         return aDefault;
       }
     }
 
     this._enabled = safeGetter("autocomplete.enabled", true);
     this._matchBehavior = safeGetter("matchBehavior", MATCH_BOUNDARY_ANYWHERE);
@@ -684,17 +682,17 @@ nsPlacesAutoComplete.prototype = {
     // Validate matchBehavior; default to MATCH_BOUNDARY_ANYWHERE.
     if (this._matchBehavior != MATCH_ANYWHERE &&
         this._matchBehavior != MATCH_BOUNDARY &&
         this._matchBehavior != MATCH_BEGINNING)
       this._matchBehavior = MATCH_BOUNDARY_ANYWHERE;
 
     // register observer
     if (aRegisterObserver) {
-      let pb = prefs.QueryInterface(Ci.nsIPrefBranch2);
+      let pb = this._prefs.QueryInterface(Ci.nsIPrefBranch2);
       pb.addObserver("", this, false);
     }
   },
 
   /**
    * Given an array of tokens, this function determines which query should be
    * ran.  It also removes any special search tokens.
    *