diff --git a/common/content/commandline.js b/common/content/commandline.js
index 564f9939..ea0a3013 100644
--- a/common/content/commandline.js
+++ b/common/content/commandline.js
@@ -255,24 +255,16 @@ var CommandWidgets = Class("CommandWidgets", {
     commandbar: Class.memoize(function () ({ group: "Cmd" })),
     statusbar: Class.memoize(function ()  ({ group: "Status" })),
 
-    _whenReady: function _whenReady(name, id, processor) {
-        Object.defineProperty(this, name, {
-            configurable: true, enumerable: true,
-            get: function get_whenReady() {
-                let elem = document.getElementById(id);
+    _whenReady: function _whenReady(name, id) {
+        let elem = document.getElementById(id);
 
-                util.waitFor(function () elem.contentDocument.documentURI === elem.getAttribute("src") &&
-                       ["viewable", "complete"].indexOf(elem.contentDocument.readyState) >= 0);
+        util.waitFor(function () elem.contentDocument.documentURI === elem.getAttribute("src") &&
+               ["viewable", "complete"].indexOf(elem.contentDocument.readyState) >= 0);
 
-                res = res || (processor || util.identity).call(self, elem);
-                return res;
-            }
-        });
-        let res, self = this;
-        return Class.replaceProperty(this, name, this[name]);
+        return elem;
     },
 
-    get completionList() this._whenReady("completionList", "dactyl-completions"),
+    completionList: Class.memoize(function () this._whenReady("completionList", "dactyl-completions"), true),
 
     completionContainer: Class.memoize(function () this.completionList.parentNode),
 
@@ -286,13 +278,13 @@ var CommandWidgets = Class("CommandWidgets", {
         return document.getElementById("dactyl-contextmenu");
     }),
 
-    get multilineOutput() this._whenReady("multilineOutput", "dactyl-multiline-output",
-                                          function (elem) {
+    multilineOutput: Class.memoize(function () {
+        let elem = this._whenReady("multilineOutput", "dactyl-multiline-output");
         elem.contentWindow.addEventListener("unload", function (event) { event.preventDefault(); }, true);
         elem.contentDocument.documentElement.id = "dactyl-multiline-output-top";
         elem.contentDocument.body.id = "dactyl-multiline-output-content";
         return elem;
-    }),
+    }, true),
 
     multilineInput: Class.memoize(function () document.getElementById("dactyl-multiline-input")),
 
@@ -576,9 +568,10 @@ var CommandLine = Module("commandline", {
 
     get completionList() {
         let node = this.widgets.active.commandline;
-        if (!node.completionList)
-            this.widgets._whenReady.call(node, "completionList", "dactyl-completions-" + node.id,
-                                         function (node) ItemList(node.id));
+        if (!node.completionList) {
+            let elem = this.widgets._whenReady("completionList", "dactyl-completions-" + node.id);
+            node.completionList = ItemList(elem.id);
+        }
         return node.completionList;
     },
 
diff --git a/common/modules/base.jsm b/common/modules/base.jsm
index b8407a1c..87f9ecc4 100644
--- a/common/modules/base.jsm
+++ b/common/modules/base.jsm
@@ -523,9 +523,11 @@ function memoize(obj, key, getter) {
         }
         return obj;
     }
+
     obj.__defineGetter__(key, function g_replaceProperty() (
         Class.replaceProperty(this.instance || this, key, null),
         Class.replaceProperty(this.instance || this, key, getter.call(this, key))));
+
     obj.__defineSetter__(key, function s_replaceProperty(val)
         Class.replaceProperty(this.instance || this, key, val));
 }
@@ -765,14 +767,33 @@ Class.extend = function extend(subclass, superclass, overrides) {
  *      property's value.
  * @return {Class.Property}
  */
-Class.memoize = function memoize(getter)
+Class.memoize = function memoize(getter, wait)
     Class.Property({
         configurable: true,
         enumerable: true,
         init: function (key) {
-            this.get = function replace() let (obj = this.instance || this) (
-                Class.replaceProperty(obj, key, null),
-                Class.replaceProperty(obj, key, getter.call(this, key)))
+            let done = false;
+            let prop = { configurable: true, enumerable: true, value: null, writable: true };
+            if (wait)
+                prop = {
+                    configurable: true, enumerable: false,
+                    get: function get() {
+                        util.waitFor(function () done);
+                        return this[key];
+                    }
+                }
+
+            this.get = function replace() {
+                let obj = this.instance || this;
+                Object.defineProperty(obj, key, prop);
+                try {
+                    return Class.replaceProperty(obj, key, getter.call(this, key));
+                }
+                finally {
+                    done = true;
+                }
+            }
+
             this.set = function replace(val) Class.replaceProperty(this.instance || this, val);
         }
     });
diff --git a/common/modules/config.jsm b/common/modules/config.jsm
index 91a2e686..f80cfcdc 100644
--- a/common/modules/config.jsm
+++ b/common/modules/config.jsm
@@ -61,13 +61,13 @@ var ConfigBase = Class("ConfigBase", {
             if (addon && !addon.getResourceURI)
                 util.reportError(Error("Don't have add-on yet"));
 
-            return !addon || addon.getResourceURI();
+            return !addon || addon.getResourceURI;
         });
 
         if (!addon)
             addon = require("addons").AddonManager.getAddonByID(this.addonID);
         return addon;
-    }),
+    }, true),
 
     /**
      * The current application locale.