diff --git a/common/content/commandline.js b/common/content/commandline.js
index c916dd30..a1d7f0b2 100644
--- a/common/content/commandline.js
+++ b/common/content/commandline.js
@@ -152,6 +152,14 @@ const CommandWidgets = Class("CommandWidgets", {
                 return this.commandbar;
             }
         });
+
+        let fontSize = util.computedStyle(document.getElementById(config.mainWindowId)).fontSize;
+        styles.registerSheet("chrome://dactyl/skin/dactyl.css");
+        styles.system.add("font-size", "chrome://dactyl/content/buffer.xhtml",
+                          "body { font-size: " + fontSize + "; }");
+    },
+    cleanup: function cleanup() {
+        styles.unregisterSheet("chrome://dactyl/skin/dactyl.css");
     },
     addElement: function (obj) {
         const self = this;
@@ -1810,12 +1818,6 @@ const CommandLine = Module("commandline", {
                     host && (!item.domains || !item.domains.some(function (d) util.isSubdomain(d, host))));
             }
         });
-    },
-    styles: function () {
-        let fontSize = util.computedStyle(document.getElementById(config.mainWindowId)).fontSize;
-        styles.registerSheet("chrome://dactyl/skin/dactyl.css");
-        styles.system.add("font-size", "chrome://dactyl/content/buffer.xhtml",
-                          "body { font-size: " + fontSize + "; }");
     }
 });
 
diff --git a/common/content/configbase.js b/common/content/configbase.js
index 459cfda0..0c27691e 100644
--- a/common/content/configbase.js
+++ b/common/content/configbase.js
@@ -65,6 +65,7 @@ const ConfigBase = Class(ModuleBase, {
      *     must be strings as entered via :set.
      */
     defaults: { guioptions: "rb" },
+    cleanups: {},
 
     /**
      * @property {[["string", "string", "function"]]} An array of
diff --git a/common/content/dactyl.js b/common/content/dactyl.js
index dbebe862..0ed9f543 100644
--- a/common/content/dactyl.js
+++ b/common/content/dactyl.js
@@ -19,7 +19,7 @@ const EVAL_ERROR = "__dactyl_eval_error";
 const EVAL_RESULT = "__dactyl_eval_result";
 const EVAL_STRING = "__dactyl_eval_string";
 
-const Dactyl = Module("dactyl", {
+const Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
     init: function () {
         window.dactyl = this;
         // cheap attempt at compatibility
@@ -30,6 +30,7 @@ const Dactyl = Module("dactyl", {
         this.indices = {};
         this.modules = modules;
         this.observers = {};
+        util.addObserver(this);
 
         this.commands["dactyl.help"] = function (event) {
             let elem = event.originalTarget;
@@ -37,6 +38,18 @@ const Dactyl = Module("dactyl", {
         };
     },
 
+    observe: {
+        "dactyl-cleanup": function () {
+            for (let [, mod] in iter(array(values(modules)).reverse()))
+                if (mod instanceof ModuleBase) {
+                    if ("cleanup" in mod)
+                        mod.cleanup();
+                    if ("destroy" in mod)
+                        mod.destroy();
+                }
+        }
+    },
+
     /** @property {string} The name of the current user profile. */
     profileName: Class.memoize(function () {
         // NOTE: services.profile.selectedProfile.name doesn't return
@@ -52,6 +65,12 @@ const Dactyl = Module("dactyl", {
         return "unknown";
     }),
 
+    cleanup: function () {
+        delete window.dactyl;
+        delete window.modules;
+        delete window.liberator;
+    },
+
     destroy: function () {
         autocommands.trigger("LeavePre", {});
         storage.saveAll();
@@ -1315,6 +1334,12 @@ const Dactyl = Module("dactyl", {
         options.add(["guioptions", "go"],
             "Show or hide certain GUI elements like the menu or toolbar",
             "charlist", config.defaults.guioptions || "", {
+
+                // FIXME: cleanup
+                cleanupValue: config.cleanups.guioptions ||
+                    "r" + [k for ([k, v] in iter(groups[1].opts))
+                           if (!document.getElementById(v[1][0]).collapsed)].join(""),
+
                 completer: function (context)
                     array(groups).map(function (g) [[k, v[0]] for ([k, v] in Iterator(g.opts))]).flatten(),
                 setter: function (value) {
diff --git a/common/content/dactyl.xul b/common/content/dactyl.xul
index 20fc35f8..5d6d6b62 100644
--- a/common/content/dactyl.xul
+++ b/common/content/dactyl.xul
@@ -8,8 +8,6 @@
  given in the LICENSE.txt file included with this file.
   -->
 
-<?xml-stylesheet href="chrome://dactyl/skin/dactyl.css" type="text/css"?>
-
 <!DOCTYPE overlay SYSTEM "dactyl.dtd" [
     <!ENTITY dactyl.content "chrome://dactyl/content/">
 ]>
diff --git a/common/content/options.js b/common/content/options.js
index 843c413c..34ce63bf 100644
--- a/common/content/options.js
+++ b/common/content/options.js
@@ -281,6 +281,8 @@ const Option = Class("Option", {
      */
     description: "",
 
+    cleanupValue: null,
+
     /**
      * @property {function(CompletionContext, Args)} This option's completer.
      * @see CompletionContext
@@ -637,6 +639,12 @@ const Options = Module("options", {
         }, window);
     },
 
+    cleanup: function cleanup() {
+        for (let opt in this)
+            if (opt.cleanupValue != null)
+                opt.value = opt.parse(opt.cleanupValue);
+    },
+
     /** @property {Iterator(Option)} @private */
     __iterator__: function ()
         values(this._options.sort(function (a, b) String.localeCompare(a.name, b.name))),
diff --git a/common/content/tabs.js b/common/content/tabs.js
index db906ff0..df717760 100644
--- a/common/content/tabs.js
+++ b/common/content/tabs.js
@@ -36,6 +36,15 @@ const Tabs = Module("tabs", {
         };
     },
 
+    cleanup: function cleanup() {
+        for (let [i, tab] in Iterator(this.allTabs)) {
+            function node(clas) document.getAnonymousElementByAttribute(tab, "class", clas);
+            for (let elem in values(["dactyl-tab-icon-number", "dactyl-tab-number"].map(node)))
+                if (elem)
+                    elem.parentNode.parentNode.removeChild(elem.parentNode);
+        }
+    },
+
     _updateTabCount: function () {
         if (dactyl.has("Gecko2"))
             for (let [i, tab] in Iterator(this.visibleTabs)) {
@@ -43,15 +52,15 @@ const Tabs = Module("tabs", {
                 if (!node("dactyl-tab-number")) {
                     let nodes = {};
                     let dom = util.xmlToDom(<xul xmlns:xul={XUL} xmlns:html={XHTML}
-                        ><xul:hbox highlight="tab-number"><xul:label key="icon" align="center" highlight="TabIconNumber" class="dactyl-tab-number"/></xul:hbox
-                        ><xul:hbox highlight="tab-number"><html:div key="label" highlight="TabNumber"/></xul:hbox
+                        ><xul:hbox highlight="tab-number"><xul:label key="icon" align="center" highlight="TabIconNumber" class="dactyl-tab-icon-number"/></xul:hbox
+                        ><xul:hbox highlight="tab-number"><html:div key="label" highlight="TabNumber" class="dactyl-tab-number"/></xul:hbox
                     ></xul>.*, document, nodes);
                     let img = node("tab-icon-image");
                     img.parentNode.appendChild(dom);
-                    tab.__defineGetter__("ordinal", function () Number(nodes.icon.value));
-                    tab.__defineSetter__("ordinal", function (i) nodes.icon.value = nodes.label.textContent = i);
+                    tab.__defineGetter__("dactylOrdinal", function () Number(nodes.icon.value));
+                    tab.__defineSetter__("dactylOrdinal", function (i) nodes.icon.value = nodes.label.textContent = i);
                 }
-                tab.ordinal = i + 1;
+                tab.dactylOrdinal = i + 1;
             }
         statusline.updateTabCount(true);
     },
diff --git a/common/modules/base.jsm b/common/modules/base.jsm
index 19529316..e2abf9d4 100644
--- a/common/modules/base.jsm
+++ b/common/modules/base.jsm
@@ -98,6 +98,7 @@ let loaded = {};
 let currentModule;
 function defineModule(name, params) {
     let module = Cu.getGlobalForObject ? Cu.getGlobalForObject(params) : params.__parent__;
+    defineModule.globals.push(module);
     module.NAME = name;
     module.EXPORTED_SYMBOLS = params.exports || [];
     defineModule.loadLog.push("defineModule " + name);
@@ -114,6 +115,7 @@ function defineModule(name, params) {
     currentModule = module;
 }
 
+defineModule.globals = [];
 defineModule.loadLog = [];
 Object.defineProperty(defineModule.loadLog, "push", {
     value: function (val) { defineModule.dump(val + "\n"); this[this.length] = val; }
diff --git a/common/modules/bookmarkcache.jsm b/common/modules/bookmarkcache.jsm
index e3d972b6..e230a077 100644
--- a/common/modules/bookmarkcache.jsm
+++ b/common/modules/bookmarkcache.jsm
@@ -42,6 +42,10 @@ const BookmarkCache = Module("BookmarkCache", XPCOM(Ci.nsINavBookmarkObserver),
         services.bookmarks.addObserver(this, false);
     },
 
+    cleanup: function cleanup() {
+        services.bookmarks.removeObserver(this);
+    },
+
     __iterator__: function () (val for ([, val] in Iterator(bookmarkcache.bookmarks))),
 
     get bookmarks() Class.replaceProperty(this, "bookmarks", this.load()),
diff --git a/common/modules/prefs.jsm b/common/modules/prefs.jsm
index d5c935e3..63ebac52 100644
--- a/common/modules/prefs.jsm
+++ b/common/modules/prefs.jsm
@@ -28,6 +28,10 @@ const Prefs = Module("prefs", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference
         this.restore();
     },
 
+    cleanup: function cleanup() {
+        this._branch.removeObserver("", this);
+    },
+
     observe: {
         "nsPref:changed": function (subject, data) {
             let observers = this._observers[data];
diff --git a/common/modules/util.jsm b/common/modules/util.jsm
index 0d52730a..b2193827 100644
--- a/common/modules/util.jsm
+++ b/common/modules/util.jsm
@@ -961,9 +961,21 @@ const Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference])
 
     observe: {
         "dactyl-cleanup": function () {
-            for (let module in values(defineModule.modules))
-                if (module.cleanup)
-                    module.cleanup();
+            // Let window cleanup functions run synchronously before we
+            // destroy modules.
+            util.timeout(function () {
+                for (let module in values(defineModule.modules))
+                    if (module.cleanup)
+                        module.cleanup();
+
+                let getOwnPropertyNames = Object.getOwnPropertyNames;
+                for each (let global in defineModule.globals.reverse())
+                    for each (let k in getOwnPropertyNames(global))
+                        try {
+                            delete global[k];
+                        }
+                        catch (e) {}
+            });
         },
         "toplevel-window-ready": function (window, data) {
             window.addEventListener("DOMContentLoaded", wrapCallback(function listener(event) {
@@ -1141,6 +1153,7 @@ const Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference])
         }
         catch (e) {
             this.dump(e);
+            try { util.dump(e.stack) } catch (e) {}
         }
     },
 
diff --git a/common/skin/dactyl.css b/common/skin/dactyl.css
index 62c92ca1..ae35761b 100644
--- a/common/skin/dactyl.css
+++ b/common/skin/dactyl.css
@@ -89,8 +89,8 @@ window[dactyl|highlight~=Bell] > * {
 }
 
 [dactyl|highlight~=CmdLine] {
-    background: inherit;
-    color: inherit;
+    background: inherit !important;
+    color: inherit !important;
 }
 [dactyl|highlight~=CmdLine],
 [dactyl|highlight~=CmdLine] > [dactyl|highlight~=CmdLine] {
@@ -123,8 +123,8 @@ statusbarpanel {
 }
 
 #dactyl-statusline-field-url {
-    background-color: inherit;
-    color: inherit;
+    background-color: inherit !important;
+    color: inherit !important;
 }
 
 /* no longer at the window's bottom right corner */
@@ -141,8 +141,8 @@ statusbarpanel {
     padding: 0px;
 }
 .dactyl-commandline-command {
-    background-color: inherit;
-    color: inherit;
+    background-color: inherit !important;
+    color: inherit !important;
     margin: 0px;
 }
 .dactyl-commandline-command html|*:focus {