diff --git a/common/modules/base.jsm b/common/modules/base.jsm
index b0abfece..22a21efc 100644
--- a/common/modules/base.jsm
+++ b/common/modules/base.jsm
@@ -733,11 +733,9 @@ function Class() {
     if (callable(args[0]))
         superclass = args.shift();
 
-    if (loaded.config && config.haveGecko("6.0a1")) // Bug 657418.
+    if (loaded.config && (config.haveGecko("5.*", "6.0") || config.haveGecko("8.0"))) // Bug 657418.
         var Constructor = function Constructor() {
-            var self = Object.create(Constructor.prototype, {
-                constructor: { value: Constructor },
-            });
+            var self = Object.create(Constructor.prototype);
             self.instance = self;
 
             if ("_metaInit_" in self && self._metaInit_)
@@ -749,9 +747,7 @@ function Class() {
     else
         var Constructor = eval(String.replace(<![CDATA[
             (function constructor(PARAMS) {
-                var self = Object.create(Constructor.prototype, {
-                    constructor: { value: Constructor },
-                });
+                var self = Object.create(Constructor.prototype);
                 self.instance = self;
 
                 if ("_metaInit_" in self && self._metaInit_)
@@ -779,9 +775,10 @@ function Class() {
 
     Class.extend(Constructor, superclass, args[0]);
     update(Constructor, args[1]);
+
     Constructor.__proto__ = superclass;
-    args = args.slice(2);
-    Array.forEach(args, function (obj) {
+
+    args.slice(2).forEach(function (obj) {
         if (callable(obj))
             obj = obj.prototype;
         update(Constructor.prototype, obj);
@@ -915,6 +912,9 @@ Class.prototype = {
      */
     init: function c_init() {},
 
+    get instance() ({}),
+    set instance(val) Class.replaceProperty(this, "instance", val),
+
     withSavedValues: function withSavedValues(names, callback, self) {
         let vals = names.map(function (name) this[name], this);
         try {
diff --git a/common/modules/config.jsm b/common/modules/config.jsm
index b706f6f0..fa03f927 100644
--- a/common/modules/config.jsm
+++ b/common/modules/config.jsm
@@ -253,10 +253,14 @@ var ConfigBase = Class("ConfigBase", {
      * Returns true if the current Gecko runtime is of the given version
      * or greater.
      *
-     * @param {string} ver The required version.
+     * @param {string} min The minimum required version. @optional
+     * @param {string} max The maximum required version. @optional
      * @returns {boolean}
      */
-    haveGecko: function (ver) services.versionCompare.compare(services.runtime.platformVersion, ver) >= 0,
+    haveGecko: function (min, max) let ({ compare } = services.versionCompare,
+                                        { platformVersion } = services.runtime)
+        (min == null || compare(platformVersion, min) >= 0) &&
+        (max == null || compare(platformVersion, max) < 0),
 
     /** Dactyl's notion of the current operating system platform. */
     OS: memoize({
diff --git a/common/modules/messages.jsm b/common/modules/messages.jsm
index 43177bfe..0473e692 100644
--- a/common/modules/messages.jsm
+++ b/common/modules/messages.jsm
@@ -17,19 +17,13 @@ var Messages = Module("messages", {
 
     init: function init(name) {
         let self = this;
-        name = name || "messages";
-
-        this.bundles = array.uniq([JSMLoader.getTarget("dactyl://locale/" + name + ".properties"),
-                                   JSMLoader.getTarget("dactyl://locale-local/" + name + ".properties"),
-                                   "resource://dactyl-locale/en-US/" + name + ".properties",
-                                   "resource://dactyl-locale-local/en-US/" + name + ".properties"])
-                            .map(services.stringBundle.createBundle)
-                            .filter(function (bundle) { try { bundle.getSimpleEnumeration(); return true; } catch (e) { return false; } });
+        this.name = name || "messages";
 
         this._ = Class("_", String, {
             init: function _(message) {
                 this.args = arguments;
             },
+            instance: {},
             message: Class.Memoize(function () {
                 let message = this.args[0];
 
@@ -42,18 +36,23 @@ var Messages = Module("messages", {
             valueOf: function valueOf() this.message,
             toString: function toString() this.message
         });
-
-        let seen = {};
-        for (let { key } in this.iterate()) {
-            if (!Set.add(seen, key))
-                this._[key] = this[key] = {
-                    __noSuchMethod__: function __(prop, args) self._.apply(self, [prop].concat(args))
-                };
-        }
     },
 
-    iterate: function () let (bundle = this.bundles[0])
-        iter(prop.QueryInterface(Ci.nsIPropertyElement) for (prop in iter(bundle.getSimpleEnumeration()))),
+    bundles: Class.Memoize(function ()
+        array.uniq([JSMLoader.getTarget("dactyl://locale/" + this.name + ".properties"),
+                    JSMLoader.getTarget("dactyl://locale-local/" + this.name + ".properties"),
+                    "resource://dactyl-locale/en-US/" + this.name + ".properties",
+                    "resource://dactyl-locale-local/en-US/" + this.name + ".properties"])
+             .map(services.stringBundle.createBundle)
+             .filter(function (bundle) { try { bundle.getSimpleEnumeration(); return true; } catch (e) { return false; } })),
+
+    iterate: function () {
+        let seen = {};
+        for (let bundle in values(this.bundles))
+            for (let { key, value } in iter(bundle.getSimpleEnumeration(), Ci.nsIPropertyElement))
+                if (!Set.add(seen, key))
+                    yield [key, value];
+    },
 
     cleanup: function cleanup() {
         services.stringBundle.flushBundles();