diff --git a/common/bootstrap.js b/common/bootstrap.js
index 0e1d864a..91a97c1c 100755
--- a/common/bootstrap.js
+++ b/common/bootstrap.js
@@ -172,7 +172,17 @@ let JSMLoader = {
         let module = this.modules[name];
         if (target)
             for each (let symbol in module.EXPORTED_SYMBOLS)
-                target[symbol] = module[symbol];
+                try {
+                    Object.defineProperty(target, symbol, {
+                        configurable: true,
+                        enumerable: true,
+                        writable: true,
+                        value: module[symbol]
+                    });
+                }
+                catch (e) {
+                    target[symbol] = module[symbol];
+                }
 
         return module;
     },
diff --git a/common/modules/base.jsm b/common/modules/base.jsm
index 3389dee9..093d6c95 100644
--- a/common/modules/base.jsm
+++ b/common/modules/base.jsm
@@ -6,10 +6,9 @@
 
 var { classes: Cc, interfaces: Ci, results: Cr, utils: Cu } = Components;
 
-if (typeof Proxy == "function")
-    var Cs = Proxy(Components.stack, {
-        get: function Cs_get(target, prop) Components.stack.caller[prop]
-    });
+var Cs = new Proxy(Components.stack, {
+    get: function Cs_get(target, prop) Components.stack.caller[prop]
+});
 
 function module(url) {
     let obj = {};
diff --git a/common/modules/main.jsm b/common/modules/main.jsm
index 31df62fd..cfb9ff91 100644
--- a/common/modules/main.jsm
+++ b/common/modules/main.jsm
@@ -110,7 +110,27 @@ var Modules = function Modules(window) {
 
     const BASES = [BASE, "resource://dactyl-local-content/"];
 
-    var jsmodules = newContext(window, false, "Dactyl `jsmodules`");
+    let proxyCache = {};
+    let proxy = new Proxy(window, {
+        get: function window_get(target, prop) {
+            // `in`, not `hasOwnProperty`, because we want to return
+            // unbound methods in `Object.prototype`
+            if (prop in proxyCache)
+                return proxyCache[prop];
+
+            let p = target[prop];
+            if (callable(p))
+                return proxyCache[prop] = p.bind(target);
+
+            return p;
+        },
+
+        set: function window_set(target, prop, val) {
+            return target[prop] = val;
+        }
+    });
+
+    var jsmodules = newContext(proxy, false, "Dactyl `jsmodules`");
     jsmodules.NAME = "jsmodules";
 
     const create = bind("create", jsmodules.Object);
@@ -120,14 +140,6 @@ var Modules = function Modules(window) {
 
         jsmodules: jsmodules,
 
-        get content() this.config.browser.contentWindow || window.content,
-
-        get document() window.document,
-
-        get navigator() window.navigator,
-
-        window: window,
-
         Module: Module,
 
         load: function load(script) {