--- a/toolkit/components/search/nsSearchService.js
+++ b/toolkit/components/search/nsSearchService.js
@@ -1394,18 +1394,16 @@ Engine.prototype = {
     return this.__file;
   },
   set _file(aValue) {
     this.__file = aValue;
   },
   // Set to true if the engine has a preferred icon (an icon that should not be
   // overridden by a non-preferred icon).
   _hasPreferredIcon: null,
-  // Whether the engine is hidden from the user.
-  _hidden: null,
   // The engine's name.
   _name: null,
   // The name of the charset used to submit the search terms.
   _queryCharset: null,
   // The engine's raw SearchForm value (URL string pointing to a search form).
   __searchForm: null,
   get _searchForm() {
     return this.__searchForm;
@@ -2169,17 +2167,16 @@ Engine.prototype = {
   _initWithJSON: function SRCH_ENG__initWithJSON(aJson) {
     this.__id = aJson._id;
     this._name = aJson._name;
     this._description = aJson.description;
     if (aJson._hasPreferredIcon == undefined)
       this._hasPreferredIcon = true;
     else
       this._hasPreferredIcon = false;
-    this._hidden = aJson._hidden;
     this._queryCharset = aJson.queryCharset || DEFAULT_QUERY_CHARSET;
     this.__searchForm = aJson.__searchForm;
     this.__installLocation = aJson._installLocation || SEARCH_APP_DIR;
     this._updateInterval = aJson._updateInterval || null;
     this._updateURL = aJson._updateURL || null;
     this._iconUpdateURL = aJson._iconUpdateURL || null;
     if (aJson._readOnly == undefined)
       this._readOnly = true;
@@ -2203,17 +2200,16 @@ Engine.prototype = {
   /**
    * Creates a JavaScript object that represents this engine.
    * @returns An object suitable for serialization as JSON.
    **/
   toJSON: function SRCH_ENG_toJSON() {
     var json = {
       _id: this._id,
       _name: this._name,
-      _hidden: this.hidden,
       description: this.description,
       __searchForm: this.__searchForm,
       _iconURL: this._iconURL,
       _iconMapObj: this._iconMapObj,
       _urls: this._urls
     };
 
     if (this._file instanceof Ci.nsILocalFile)
@@ -2396,24 +2392,21 @@ Engine.prototype = {
     return this._identifier = leaf.substring(0, ext);
   },
 
   get description() {
     return this._description;
   },
 
   get hidden() {
-    if (this._hidden === null)
-      this._hidden = engineMetadataService.getAttr(this, "hidden") || false;
-    return this._hidden;
+    return engineMetadataService.getAttr(this, "hidden") || false;
   },
   set hidden(val) {
     var value = !!val;
-    if (value != this._hidden) {
-      this._hidden = value;
+    if (value != this.hidden) {
       engineMetadataService.setAttr(this, "hidden", value);
       notifyAction(this, SEARCH_ENGINE_CHANGED);
     }
   },
 
   get iconURI() {
     if (this._iconURI)
       return this._iconURI;

--- a/toolkit/components/search/tests/xpcshell/data/search.json
+++ b/toolkit/components/search/tests/xpcshell/data/search.json
@@ -4,17 +4,16 @@
   "locale": "en-US",
   "directories": {
     "[profile]/searchplugins": {
       "lastModifiedTime": 1333761316000,
       "engines": [
         {
           "_id": "[app]/test-search-engine.xml",
           "_name": "Test search engine",
-          "_hidden": false,
           "description": "A test search engine (based on Google search)",
           "extensionID": "test-addon-id@mozilla.org",
           "__searchForm": "http://www.google.com/",
           "_iconURL": "data:image/png;base64,AAABAAEAEBAAAAEAGABoAwAAFgAAACgAAAAQAAAAIAAAAAEAGAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAADs9Pt8xetPtu9FsfFNtu%2BTzvb2%2B%2Fne4dFJeBw0egA%2FfAJAfAA8ewBBegAAAAD%2B%2FPtft98Mp%2BwWsfAVsvEbs%2FQeqvF8xO7%2F%2F%2F63yqkxdgM7gwE%2FggM%2BfQA%2BegBDeQDe7PIbotgQufcMufEPtfIPsvAbs%2FQvq%2Bfz%2Bf%2F%2B%2B%2FZKhR05hgBBhQI8hgBAgAI9ewD0%2B%2Fg3pswAtO8Cxf4Kw%2FsJvvYAqupKsNv%2B%2Fv7%2F%2FP5VkSU0iQA7jQA9hgBDgQU%2BfQH%2F%2Ff%2FQ6fM4sM4KsN8AteMCruIqqdbZ7PH8%2Fv%2Fg6Nc%2Fhg05kAA8jAM9iQI%2BhQA%2BgQDQu6b97uv%2F%2F%2F7V8Pqw3eiWz97q8%2Ff%2F%2F%2F%2F7%2FPptpkkqjQE4kwA7kAA5iwI8iAA8hQCOSSKdXjiyflbAkG7u2s%2F%2B%2F%2F39%2F%2F7r8utrqEYtjQE8lgA7kwA7kwA9jwA9igA9hACiWSekVRyeSgiYSBHx6N%2F%2B%2Fv7k7OFRmiYtlAA5lwI7lwI4lAA7kgI9jwE9iwI4iQCoVhWcTxCmb0K%2BooT8%2Fv%2F7%2F%2F%2FJ2r8fdwI1mwA3mQA3mgA8lAE8lAE4jwA9iwE%2BhwGfXifWvqz%2B%2Ff%2F58u%2Fev6Dt4tr%2B%2F%2F2ZuIUsggA7mgM6mAM3lgA5lgA6kQE%2FkwBChwHt4dv%2F%2F%2F728ei1bCi7VAC5XQ7kz7n%2F%2F%2F6bsZkgcB03lQA9lgM7kwA2iQktZToPK4r9%2F%2F%2F9%2F%2F%2FSqYK5UwDKZAS9WALIkFn%2B%2F%2F3%2F%2BP8oKccGGcIRJrERILYFEMwAAuEAAdX%2F%2Ff7%2F%2FP%2B%2BfDvGXQLIZgLEWgLOjlf7%2F%2F%2F%2F%2F%2F9QU90EAPQAAf8DAP0AAfMAAOUDAtr%2F%2F%2F%2F7%2B%2Fu2bCTIYwDPZgDBWQDSr4P%2F%2Fv%2F%2F%2FP5GRuABAPkAA%2FwBAfkDAPAAAesAAN%2F%2F%2B%2Fz%2F%2F%2F64g1C5VwDMYwK8Yg7y5tz8%2Fv%2FV1PYKDOcAAP0DAf4AAf0AAfYEAOwAAuAAAAD%2F%2FPvi28ymXyChTATRrIb8%2F%2F3v8fk6P8MAAdUCAvoAAP0CAP0AAfYAAO4AAACAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAQAA",
           "_urls": [
             {
               "template": "http://suggestqueries.google.com/complete/search?output=firefox&client=firefox&hl={moz:locale}&q={searchTerms}",
               "rels": [