diff --git a/common/content/contexts.js b/common/content/contexts.js
index 714b45c4..caa5b8c5 100644
--- a/common/content/contexts.js
+++ b/common/content/contexts.js
@@ -148,6 +148,23 @@ var Contexts = Module("contexts", {
 
     context: null,
 
+    /**
+     * Returns a frame object describing the currently executing
+     * command, if applicable, otherwise returns the passed frame.
+     *
+     * @param {nsIStackFrame} frame
+     */
+    getCaller: function getCaller(frame) {
+        if (this.context && this.context.file)
+           return {
+                __proto__: frame,
+                filename: this.context.file[0] == "[" ? this.context.file
+                                                      : services.io.newFileURI(File(this.context.file)).spec,
+                lineNumber: this.context.line
+            };
+        return frame;
+    },
+
     groups: Class.memoize(function () Object.create(Group.groupsProto, {
         groups: { value: this.activeGroups().filter(function (g) g.filter(buffer.uri)) }
     })),
@@ -216,8 +233,8 @@ var Contexts = Module("contexts", {
     getGroup: function getGroup(name, hive) {
         if (name === "default")
             var group = this.context && this.context.context && this.context.context.GROUP;
-        else
-            group = set.has(this.groupMap, name) && this.groupMap[name];
+        else if (set.has(this.groupMap, name))
+            group = this.groupMap[name];
 
         if (group && hive)
             return group[hive];
diff --git a/common/content/mappings.js b/common/content/mappings.js
index 9512e087..6f1c81af 100644
--- a/common/content/mappings.js
+++ b/common/content/mappings.js
@@ -170,7 +170,7 @@ var MapHive = Class("MapHive", Group.Hive, {
         extra = extra || {};
 
         let map = Map(modes, keys, description, action, extra);
-        map.definedAt = Commands.getCaller(Components.stack.caller);
+        map.definedAt = contexts.getCaller(Components.stack.caller);
         map.hive = this;
 
         if (this.name !== "builtin")
@@ -341,7 +341,7 @@ var Mappings = Module("mappings", {
      */
     add: function () {
         let map = this.builtin.add.apply(this.builtin, arguments);
-        map.definedAt = Commands.getCaller(Components.stack.caller);
+        map.definedAt = contexts.getCaller(Components.stack.caller);
         return map;
     },
 
@@ -358,7 +358,7 @@ var Mappings = Module("mappings", {
      */
     addUserMap: function () {
         let map = this.user.add.apply(this.user, arguments);
-        map.definedAt = Commands.getCaller(Components.stack.caller);
+        map.definedAt = contexts.getCaller(Components.stack.caller);
         return map;
     },
 
@@ -454,6 +454,9 @@ var Mappings = Module("mappings", {
                 if (!rhs) // list the mapping
                     mappings.list(mapmodes, mappings.expandLeader(lhs), hives);
                 else {
+                    util.assert(args["-group"] !== mappings.builtin,
+                                "Cannot change mappings in the builtin group");
+
                     args["-group"].add(mapmodes, [lhs],
                         args["-description"],
                         contexts.bindMacro(args, "-keys", function (params) params),
@@ -572,6 +575,9 @@ var Mappings = Module("mappings", {
             commands.add([ch + "mapc[lear]"],
                 "Remove all mappings" + modeDescription,
                 function (args) {
+                    util.assert(args["-group"] !== mappings.builtin,
+                                "Cannot change mappings in the builtin group");
+
                     let mapmodes = array.uniq(args["-modes"].map(findMode));
                     mapmodes.forEach(function (mode) {
                         args["-group"].clear(mode);
@@ -593,6 +599,9 @@ var Mappings = Module("mappings", {
             commands.add([ch + "unm[ap]"],
                 "Remove a mapping" + modeDescription,
                 function (args) {
+                    util.assert(args["-group"] !== mappings.builtin,
+                                "Cannot change mappings in the builtin group");
+
                     let mapmodes = array.uniq(args["-modes"].map(findMode));
 
                     let found = false;
diff --git a/common/content/commands.js b/common/modules/commands.jsm
similarity index 78%
rename from common/content/commands.js
rename to common/modules/commands.jsm
index c9118a6a..c426c106 100644
--- a/common/content/commands.js
+++ b/common/modules/commands.jsm
@@ -6,6 +6,15 @@
 // given in the LICENSE.txt file included with this file.
 "use strict";
 
+try {
+
+Components.utils.import("resource://dactyl/bootstrap.jsm");
+defineModule("commands", {
+    exports: ["ArgType", "Command", "Commands", "CommandOption", "Ex", "commands"],
+    use: ["config", "options", "template", "util"]
+}, this);
+
+
 /** @scope modules */
 
 /**
@@ -141,6 +150,8 @@ var Command = Class("Command", {
      * @param {Object} modifiers Any modifiers to be passed to {@link #action}.
      */
     execute: function (args, modifiers) {
+        const { dactyl } = this.modules;
+
         let context = args.context;
         if (this.deprecated && !set.add(this.complained, context ? context.file : "[Command Line]")) {
             let loc = contexts.context ? context.file + ":" + context.line + ": " : "";
@@ -190,7 +201,7 @@ var Command = Class("Command", {
      * @returns {Args}
      * @see Commands#parseArgs
      */
-    parseArgs: function (args, complete, extra) commands.parseArgs(args, {
+    parseArgs: function parseArgs(args, complete, extra) this.modules.commands.parseArgs(args, {
         __proto__: this,
         complete: complete,
         extra: extra
@@ -265,8 +276,9 @@ var Command = Class("Command", {
     optionMap: Class.memoize(function () array(this.options)
                 .map(function (opt) opt.names.map(function (name) [name, opt]))
                 .flatten().toObject()),
-    newArgs: function () {
+    newArgs: function (base) {
         let res = [];
+        update(res, base);
         res.__proto__ = this.argsPrototype;
         return res;
     },
@@ -279,8 +291,6 @@ var Command = Class("Command", {
 
                 command: this,
 
-                get context() contexts.context,
-
                 explicitOpts: Class.memoize(function () ({})),
 
                 has: function (opt) set.has(this.explicitOpts, opt) || typeof opt === "number" && set.has(this, opt),
@@ -290,13 +300,13 @@ var Command = Class("Command", {
                 // TODO: string: Class.memoize(function () { ... }),
                 verify: function verify() {
                     if (this.command.argCount) {
-                        dactyl.assert((this.length > 0 || !/^[1+]$/.test(this.command.argCount)) &&
-                                      (this.literal == null || !/[1+]/.test(this.command.argCount) || /\S/.test(this.literalArg || "")),
-                                      "E471: Argument required");
+                        util.assert((this.length > 0 || !/^[1+]$/.test(this.command.argCount)) &&
+                                    (this.literal == null || !/[1+]/.test(this.command.argCount) || /\S/.test(this.literalArg || "")),
+                                     "E471: Argument required");
 
-                        dactyl.assert((this.length == 0 || this.command.argCount !== "0") &&
-                                      (this.length <= 1 || !/^[01?]$/.test(this.command.argCount)),
-                                      "E488: Trailing characters");
+                        util.assert((this.length == 0 || this.command.argCount !== "0") &&
+                                    (this.length <= 1 || !/^[01?]$/.test(this.command.argCount)),
+                                    "E488: Trailing characters");
                     }
                 }
             })),
@@ -352,11 +362,16 @@ var Command = Class("Command", {
 });
 
 // Prototype.
-var ex = {
+var Ex = Module("Ex", {
+    Local: function Local(dactyl, modules, window) ({
+        get commands() modules.commands,
+        get context() modules.contexts.context
+    }),
+
     _args: function (cmd, args) {
         args = Array.slice(args);
 
-        let res = cmd.newArgs();
+        let res = cmd.newArgs({ context: this.context });
         if (isObject(args[0]))
             for (let [k, v] in Iterator(args.shift()))
                 if (k == "!")
@@ -366,8 +381,8 @@ var ex = {
                 else {
                     let opt = cmd.optionMap["-" + k];
                     let val = opt.type && opt.type.parse(v);
-                    dactyl.assert(val != null && (typeof val !== "number" || !isNaN(val)),
-                                  "No such option: " + k);
+                    util.assert(val != null && (typeof val !== "number" || !isNaN(val)),
+                                "No such option: " + k);
                     Class.replaceProperty(args, opt.names[0], val);
                     args.explicitOpts[opt.names[0]] = val;
                 }
@@ -376,137 +391,264 @@ var ex = {
         return res;
     },
 
-    _complete: function (cmd)
+    _complete: function (cmd) let (self = this)
         function _complete(context, func, obj, args) {
-            args = ex._args(cmd, args);
+            args = self._args(cmd, args);
             args.completeArg = args.length - 1;
             if (cmd.completer && args.length)
                 return cmd.completer(context, args);
         },
 
     _run: function (name) {
-        let cmd = commands.get(name);
-        dactyl.assert(cmd, "No such command");
+        const self = this;
+        let cmd = this.commands.get(name);
+        util.assert(cmd, "No such command");
 
         return update(function exCommand(options) {
-            let args = ex._args(cmd, arguments);
+            let args = self._args(cmd, arguments);
             args.verify();
             return cmd.execute(args);
         }, {
-            dactylCompleter: ex._complete(cmd)
+            dactylCompleter: self._complete(cmd)
         });
     },
 
     __noSuchMethod__: function (meth, args) this._run(meth).apply(this, args)
-};
-
-var CommandHive = Class("CommandHive", Group.Hive, {
-    init: function init(group) {
-        init.supercall(this, group);
-        this._map = {};
-        this._list = [];
-    },
-
-    /** @property {Iterator(Command)} @private */
-    __iterator__: function () array.iterValues(this._list.sort(function (a, b) a.name > b.name)),
-
-    /** @property {string} The last executed Ex command line. */
-    repeat: null,
-
-    /**
-     * Adds a new command.
-     *
-     * @param {string[]} names The names by which this command can be
-     *     invoked. The first name specified is the command's canonical
-     *     name.
-     * @param {string} description A description of the command.
-     * @param {function} action The action invoked by this command.
-     * @param {Object} extra An optional extra configuration hash.
-     * @optional
-     */
-    add: function (names, description, action, extra, replace) {
-        extra = extra || {};
-        if (!extra.definedAt)
-            extra.definedAt = Commands.getCaller(Components.stack.caller);
-
-        extra.hive = this;
-        extra.parsedSpecs = Command.parseSpecs(names);
-
-        let names = array.flatten(extra.parsedSpecs);
-        let name = names[0];
-
-        dactyl.assert(!names.some(function (name) name in commands.builtin._map),
-                      "E182: Can't replace non-user command: " + name);
-
-        dactyl.assert(replace || names.every(function (name) !(name in this._map), this),
-                      "Not replacing command " + name);
-
-        for (let name in values(names)) {
-            ex.__defineGetter__(name, function () this._run(name));
-            if (name in this._map)
-                this.remove(name);
-        }
-
-        let self = this;
-        let closure = function () self._map[name];
-
-        memoize(this._map, name, function () Command(names, description, action, extra));
-        memoize(this._list, this._list.length, closure);
-        for (let alias in values(names.slice(1)))
-            memoize(this._map, alias, closure);
-
-        return name;
-    },
-    _add: function (names, description, action, extra, replace) {
-        extra = extra || {};
-        extra.definedAt = Commands.getCaller(Components.stack.caller.caller);
-        return this.add.apply(this, arguments);
-    },
-
-    /**
-     * Returns the command with matching *name*.
-     *
-     * @param {string} name The name of the command to return. This can be
-     *     any of the command's names.
-     * @param {boolean} full If true, only return a command if one of
-     *     its names matches *name* exactly.
-     * @returns {Command}
-     */
-    get: function (name, full) this._map[name]
-            || !full && array.nth(this._list, function (cmd) cmd.hasName(name), 0)
-            || null,
-
-    /**
-     * Remove the user-defined command with matching *name*.
-     *
-     * @param {string} name The name of the command to remove. This can be
-     *     any of the command's names.
-     */
-    remove: function (name) {
-        dactyl.assert(this.group !== contexts.default,
-                      "Cannot delete non-user commands");
-
-        let cmd = this.get(name);
-        this._list = this._list.filter(function (c) c !== cmd);
-        for (let name in values(cmd.names))
-            delete this._map[name];
-    }
 });
 
 /**
  * @instance commands
  */
 var Commands = Module("commands", {
-    init: function () {
-        this.user = contexts.hives.commands.user;
-        this.builtin = contexts.hives.commands.builtin;
-    },
+    lazyInit: true,
 
-    hives: Group.Hives("commands", CommandHive),
+    Local: function Local(dactyl, modules, window) let ({ Group, contexts } = modules) ({
+        init: function () {
+            this.Command = Class("Command", Command, { modules: modules });
+            this.user = contexts.hives.commands.user;
+            this.builtin = contexts.hives.commands.builtin;
+        },
 
-    get allHives() contexts.allGroups.commands,
+        get context() contexts.context,
 
-    get userHives() this.allHives.filter(function (h) h !== this.builtin, this),
+        get readHeredoc() modules.io.readHeredoc,
+
+        hives: Group.Hives("commands", Class("CommandHive", Group.Hive, {
+            init: function init(group) {
+                init.supercall(this, group);
+                this._map = {};
+                this._list = [];
+            },
+
+            /** @property {Iterator(Command)} @private */
+            __iterator__: function () array.iterValues(this._list.sort(function (a, b) a.name > b.name)),
+
+            /** @property {string} The last executed Ex command line. */
+            repeat: null,
+
+            /**
+             * Adds a new command.
+             *
+             * @param {string[]} names The names by which this command can be
+             *     invoked. The first name specified is the command's canonical
+             *     name.
+             * @param {string} description A description of the command.
+             * @param {function} action The action invoked by this command.
+             * @param {Object} extra An optional extra configuration hash.
+             * @optional
+             */
+            add: function (names, description, action, extra, replace) {
+                const { commands } = modules;
+
+                extra = extra || {};
+                if (!extra.definedAt)
+                    extra.definedAt = contexts.getCaller(Components.stack.caller);
+
+                extra.hive = this;
+                extra.parsedSpecs = Command.parseSpecs(names);
+
+                let names = array.flatten(extra.parsedSpecs);
+                let name = names[0];
+
+                util.assert(!names.some(function (name) name in commands.builtin._map),
+                            "E182: Can't replace non-user command: " + name);
+
+                util.assert(replace || names.every(function (name) !(name in this._map), this),
+                            "Not replacing command " + name);
+
+                for (let name in values(names)) {
+                    ex.__defineGetter__(name, function () this._run(name));
+                    if (name in this._map)
+                        this.remove(name);
+                }
+
+                let self = this;
+                let closure = function () self._map[name];
+
+                memoize(this._map, name, function () commands.Command(names, description, action, extra));
+                memoize(this._list, this._list.length, closure);
+                for (let alias in values(names.slice(1)))
+                    memoize(this._map, alias, closure);
+
+                return name;
+            },
+
+            _add: function (names, description, action, extra, replace) {
+                extra = extra || {};
+                extra.definedAt = contexts.getCaller(Components.stack.caller.caller);
+                return this.add.apply(this, arguments);
+            },
+
+            /**
+             * Clear all commands.
+             * @returns {Command}
+             */
+            clear: function clear() {
+                util.assert(this.group !== contexts.default,
+                            "Cannot delete non-user commands");
+                this._map = {};
+                this._list = [];
+            },
+
+            /**
+             * Returns the command with matching *name*.
+             *
+             * @param {string} name The name of the command to return. This can be
+             *     any of the command's names.
+             * @param {boolean} full If true, only return a command if one of
+             *     its names matches *name* exactly.
+             * @returns {Command}
+             */
+            get: function get(name, full) this._map[name]
+                    || !full && array.nth(this._list, function (cmd) cmd.hasName(name), 0)
+                    || null,
+
+            /**
+             * Remove the user-defined command with matching *name*.
+             *
+             * @param {string} name The name of the command to remove. This can be
+             *     any of the command's names.
+             */
+            remove: function remove(name) {
+                util.assert(this.group !== contexts.default,
+                            "Cannot delete non-user commands");
+
+                let cmd = this.get(name);
+                this._list = this._list.filter(function (c) c !== cmd);
+                for (let name in values(cmd.names))
+                    delete this._map[name];
+            }
+        })),
+
+        get allHives() contexts.allGroups.commands,
+
+        get userHives() this.allHives.filter(function (h) h !== this.builtin, this),
+
+        /**
+         * Executes an Ex command script.
+         *
+         * @param {string} string A string containing the commands to execute.
+         * @param {object} tokens An optional object containing tokens to be
+         *      interpolated into the command string.
+         * @param {object} args Optional arguments object to be passed to
+         *      command actions.
+         * @param {object} context An object containing information about
+         *      the file that is being or has been sourced to obtain the
+         *      command string.
+         */
+        execute: function (string, tokens, silent, args, context) {
+            contexts.withContext(context || this.context || { file: "[Command Line]", line: 1 },
+                                 function (context) {
+                modules.io.withSavedValues(["readHeredoc"], function () {
+                    this.readHeredoc = function (end) {
+                        let res = [];
+                        contexts.context.line++;
+                        while (++i < lines.length) {
+                            if (lines[i] === end)
+                                return res.join("\n");
+                            res.push(lines[i]);
+                        }
+                        util.assert(false, "Unexpected end of file waiting for " + end);
+                    };
+
+                    args = update({}, args || {});
+
+                    if (tokens && !callable(string))
+                        string = util.compileMacro(string, true);
+                    if (callable(string))
+                        string = string(tokens || {});
+
+                    let lines = string.split(/\r\n|[\r\n]/);
+                    let startLine = context.line;
+
+                    for (var i = 0; i < lines.length && !context.finished; i++) {
+                        // Deal with editors from Silly OSs.
+                        let line = lines[i].replace(/\r$/, "");
+
+                        context.line = startLine + i;
+
+                        // Process escaped new lines
+                        while (i < lines.length && /^\s*\\/.test(lines[i + 1]))
+                            line += "\n" + lines[++i].replace(/^\s*\\/, "");
+
+                        try {
+                            dactyl.execute(line, args);
+                        }
+                        catch (e) {
+                            if (!silent) {
+                                e.message = context.file + ":" + context.line + ": " + e.message;
+                                dactyl.reportError(e, true);
+                            }
+                        }
+                    }
+                });
+            });
+        },
+
+        /**
+         * Displays a list of user-defined commands.
+         */
+        list: function list() {
+            function completerToString(completer) {
+                if (completer)
+                    return [k for ([k, v] in Iterator(config.completers)) if (completer == completion.closure[v])][0] || "custom";
+                return "";
+            }
+
+            if (!this.userHives.some(function (h) h._list.length))
+                dactyl.echomsg("No user-defined commands found");
+            else
+                modules.commandline.commandOutput(
+                    <table>
+                        <tr highlight="Title">
+                            <td/>
+                            <td style="padding-right: 1em;"></td>
+                            <td style="padding-right: 1ex;">Name</td>
+                            <td style="padding-right: 1ex;">Args</td>
+                            <td style="padding-right: 1ex;">Range</td>
+                            <td style="padding-right: 1ex;">Complete</td>
+                            <td style="padding-right: 1ex;">Definition</td>
+                        </tr>
+                        <col style="min-width: 6em; padding-right: 1em;"/>
+                        {
+                            template.map(this.userHives, function (hive) let (i = 0)
+                                <tr style="height: .5ex;"/> +
+                                template.map(hive, function (cmd)
+                                    template.map(cmd.names, function (name)
+                                    <tr>
+                                        <td highlight="Title">{!i++ ? hive.name : ""}</td>
+                                        <td>{cmd.bang ? "!" : " "}</td>
+                                        <td>{cmd.name}</td>
+                                        <td>{cmd.argCount}</td>
+                                        <td>{cmd.count ? "0c" : ""}</td>
+                                        <td>{completerToString(cmd.completer)}</td>
+                                        <td>{cmd.replacementText || "function () { ... }"}</td>
+                                    </tr>)) +
+                                <tr style="height: .5ex;"/>)
+                        }
+                    </table>);
+        }
+    }),
 
     /**
      * @property Indicates that no count was specified for this
@@ -532,7 +674,7 @@ var Commands = Module("commands", {
 
     add: function () this.builtin._add.apply(this.builtin, arguments),
     addUserCommand: deprecated("commands.user.add", { get: function addUserCommand() this.user.closure._add }),
-    getUserCommands: deprecated("iter(commands.user)", function getUserCommands() iter(commands.user).toArray()),
+    getUserCommands: deprecated("iter(commands.user)", function getUserCommands() iter(this.user).toArray()),
     removeUserCommand: deprecated("commands.user.remove", { get: function removeUserCommand() this.user.closure.remove }),
 
     /**
@@ -578,111 +720,6 @@ var Commands = Module("commands", {
     get: function (name, full) iter(this.hives).map(function ([i, hive]) hive.get(name, full))
                                                .nth(util.identity, 0),
 
-    /**
-     * Displays a list of user-defined commands.
-     */
-    list: function list() {
-        function completerToString(completer) {
-            if (completer)
-                return [k for ([k, v] in Iterator(config.completers)) if (completer == completion.closure[v])][0] || "custom";
-            return "";
-        }
-
-        if (!commands.userHives.some(function (h) h._list.length))
-            dactyl.echomsg("No user-defined commands found");
-        else
-            commandline.commandOutput(
-                <table>
-                    <tr highlight="Title">
-                        <td/>
-                        <td style="padding-right: 1em;"></td>
-                        <td style="padding-right: 1ex;">Name</td>
-                        <td style="padding-right: 1ex;">Args</td>
-                        <td style="padding-right: 1ex;">Range</td>
-                        <td style="padding-right: 1ex;">Complete</td>
-                        <td style="padding-right: 1ex;">Definition</td>
-                    </tr>
-                    <col style="min-width: 6em; padding-right: 1em;"/>
-                    {
-                        template.map(commands.userHives, function (hive) let (i = 0)
-                            <tr style="height: .5ex;"/> +
-                            template.map(hive, function (cmd)
-                                template.map(cmd.names, function (name)
-                                <tr>
-                                    <td highlight="Title">{!i++ ? hive.name : ""}</td>
-                                    <td>{cmd.bang ? "!" : " "}</td>
-                                    <td>{cmd.name}</td>
-                                    <td>{cmd.argCount}</td>
-                                    <td>{cmd.count ? "0c" : ""}</td>
-                                    <td>{completerToString(cmd.completer)}</td>
-                                    <td>{cmd.replacementText || "function () { ... }"}</td>
-                                </tr>)) +
-                            <tr style="height: .5ex;"/>)
-                    }
-                </table>);
-    },
-
-    /**
-     * Executes an Ex command script.
-     *
-     * @param {string} string A string containing the commands to execute.
-     * @param {object} tokens An optional object containing tokens to be
-     *      interpolated into the command string.
-     * @param {object} args Optional arguments object to be passed to
-     *      command actions.
-     * @param {object} context An object containing information about
-     *      the file that is being or has been sourced to obtain the
-     *      command string.
-     */
-    execute: function (string, tokens, silent, args, context) {
-        contexts.withContext(context || this.context || { file: "[Command Line]", line: 1 },
-                             function (context) {
-            io.withSavedValues(["readHeredoc"], function () {
-                this.readHeredoc = function (end) {
-                    let res = [];
-                    contexts.context.line++;
-                    while (++i < lines.length) {
-                        if (lines[i] === end)
-                            return res.join("\n");
-                        res.push(lines[i]);
-                    }
-                    dactyl.assert(false, "Unexpected end of file waiting for " + end);
-                };
-
-                args = update({}, args || {});
-
-                if (tokens && !callable(string))
-                    string = util.compileMacro(string, true);
-                if (callable(string))
-                    string = string(tokens || {});
-
-                let lines = string.split(/\r\n|[\r\n]/);
-                let startLine = context.line;
-
-                for (var i = 0; i < lines.length && !context.finished; i++) {
-                    // Deal with editors from Silly OSs.
-                    let line = lines[i].replace(/\r$/, "");
-
-                    context.line = startLine + i;
-
-                    // Process escaped new lines
-                    while (i < lines.length && /^\s*\\/.test(lines[i + 1]))
-                        line += "\n" + lines[++i].replace(/^\s*\\/, "");
-
-                    try {
-                        dactyl.execute(line, args);
-                    }
-                    catch (e) {
-                        if (!silent) {
-                            e.message = context.file + ":" + context.line + ": " + e.message;
-                            dactyl.reportError(e, true);
-                        }
-                    }
-                }
-            });
-        });
-    },
-
     /**
      * Returns true if a command invocation contains a URL referring to the
      * domain *host*.
@@ -698,7 +735,7 @@ var Commands = Module("commands", {
                     return true;
         }
         catch (e) {
-            dactyl.reportError(e);
+            util.reportError(e);
         }
         return false;
     },
@@ -764,7 +801,9 @@ var Commands = Module("commands", {
      *     Args object.
      * @returns {Args}
      */
-    parseArgs: function (str, params) {
+    parseArgs: function parseArgs(str, params) {
+        const self = this;
+
         function getNextArg(str, _keepQuotes) {
             if (arguments.length < 2)
                 _keepQuotes = keepQuotes;
@@ -774,7 +813,7 @@ var Commands = Module("commands", {
                 let count = arg.length + 2;
                 if (complete)
                     return [count, "", ""];
-                return [count, io.readHeredoc(arg), ""];
+                return [count, self.readHeredoc(arg), ""];
             }
 
             let [count, arg, quote] = Commands.parseArg(str, null, _keepQuotes);
@@ -795,7 +834,7 @@ var Commands = Module("commands", {
             if (!argCount)
                 argCount = "*";
 
-            var args = (params.newArgs || Array).call(params); // parsed options
+            var args = params.newArgs ? params.newArgs() : [];
             args.string = str; // for access to the unparsed string
 
             // FIXME!
@@ -832,7 +871,7 @@ var Commands = Module("commands", {
                 if (complete)
                     complete.message = error;
                 else
-                    dactyl.assert(false, error);
+                    util.assert(false, error);
             };
 
             outer:
@@ -873,7 +912,7 @@ var Commands = Module("commands", {
                                 if (sep == "=" || /\s/.test(sep) && opt.type != CommandOption.NOARG) {
                                     [count, quoted, quote, error] = getNextArg(sub.substr(optname.length + 1), true);
                                     arg = Option.dequote(quoted);
-                                    dactyl.assert(!error, error);
+                                    util.assert(!error, error);
 
                                     // if we add the argument to an option after a space, it MUST not be empty
                                     if (sep != "=" && !quote && arg.length == 0)
@@ -974,7 +1013,7 @@ var Commands = Module("commands", {
 
                 // if not an option, treat this token as an argument
                 let [count, arg, quote, error] = getNextArg(sub);
-                dactyl.assert(!error, error);
+                util.assert(!error, error);
 
                 if (complete) {
                     args.quote = Commands.complQuote[quote] || Commands.complQuote[""];
@@ -1127,7 +1166,7 @@ var Commands = Module("commands", {
     parseCommands: function (str, complete) {
         do {
             let [count, cmd, bang, args, len] = commands.parseCommand(str);
-            let command = commands.get(cmd || "");
+            let command = this.get(cmd || "");
 
             if (command == null) {
                 yield [null, { commandString: str }];
@@ -1142,7 +1181,8 @@ var Commands = Module("commands", {
             if (!complete || /(\w|^)[!\s]/.test(str))
                 args = command.parseArgs(args, context, { count: count, bang: bang });
             else
-                args = commands.parseArgs(args, { extra: { count: count, bang: bang } });
+                args = this.parseArgs(args, { extra: { count: count, bang: bang } });
+            args.context = this.context;
             args.commandName = cmd;
             args.commandString = str.substr(0, len) + args.string;
             str = args.trailing;
@@ -1175,23 +1215,6 @@ var Commands = Module("commands", {
     get quoteArg() Commands.quoteArg // XXX: better somewhere else?
 
 }, {
-    /**
-     * Returns a frame object describing the currently executing
-     * command, if applicable, otherwise returns the passed frame.
-     *
-     * @param {nsIStackFrame} frame
-     */
-    getCaller: function (frame) {
-        if (contexts.context)
-           return {
-                __proto__: frame,
-                filename: contexts.context.file[0] == "[" ? contexts.context.file :
-                            services.io.newFileURI(File(contexts.context.file)).spec,
-                lineNumber: contexts.context.line
-            };
-        return frame;
-    },
-
     // returns [count, parsed_argument]
     parseArg: function parseArg(str, sep, keepQuotes) {
         let arg = "";
@@ -1233,15 +1256,19 @@ var Commands = Module("commands", {
         /[\s"'\\]|^$|^-/.test(str) ? "'"
                                    : ""](str)
 }, {
-    completion: function () {
+    completion: function initCompletion(dactyl, modules, window) {
+        const { completion } = modules;
+
         completion.command = function command(context) {
             context.title = ["Command"];
             context.keys = { text: "longNames", description: "description" };
-            context.generate = function () commands.hives.map(function (h) h._list).flatten();
+            context.generate = function () modules.commands.hives.map(function (h) h._list).flatten();
         };
 
         // provides completions for ex commands, including their arguments
         completion.ex = function ex(context) {
+            const { commands } = modules;
+
             // if there is no space between the command name and the cursor
             // then get completions of the command name
             for (var [command, args] in commands.parseCommands(context.filter, context))
@@ -1280,18 +1307,20 @@ var Commands = Module("commands", {
                 }
             }
             catch (e) {
-                dactyl.reportError(e);
+                util.reportError(e);
             }
         };
 
-        completion.userCommand = function userCommand(context) {
+        completion.userCommand = function userCommand(context, group) {
             context.title = ["User Command", "Definition"];
             context.keys = { text: "name", description: "replacementText" };
-            context.completions = commands.getUserCommands();
+            context.completions = group || modules.commands.user;
         };
     },
 
-    commands: function () {
+    commands: function (dactyl, modules, window) {
+        const { commands, contexts } = modules;
+
         // TODO: Vim allows commands to be defined without {rep} if there are {attr}s
         // specified - useful?
         commands.add(["com[mand]"],
@@ -1299,12 +1328,15 @@ var Commands = Module("commands", {
             function (args) {
                 let cmd = args[0];
 
-                dactyl.assert(!cmd || cmd.split(",").every(commands.validName.closure.test),
-                              "E182: Invalid command name");
+                util.assert(!cmd || cmd.split(",").every(commands.validName.closure.test),
+                            "E182: Invalid command name");
 
                 if (!args.literalArg)
                     commands.list();
                 else {
+                    util.assert(args["-group"] !== commands.builtin,
+                                "Cannot change commands in the builtin group");
+
                     let completer  = args["-complete"];
                     let completerFunc = null; // default to no completion for user commands
 
@@ -1333,7 +1365,7 @@ var Commands = Module("commands", {
                             };
                         }
                         else
-                            completerFunc = function (context) completion.closure[config.completers[completer]](context);
+                            completerFunc = function (context) modules.completion.closure[config.completers[completer]](context);
                     }
 
                     let added = args["-group"].add(cmd.split(","),
@@ -1364,8 +1396,9 @@ var Commands = Module("commands", {
             }, {
                 bang: true,
                 completer: function (context, args) {
+                    const { completion } = modules;
                     if (args.completeArg == 0)
-                        completion.userCommand(context);
+                        completion.userCommand(context, args["-group"]);
                     else
                         args["-javascript"] ? completion.javascript(context) : completion.ex(context);
                 },
@@ -1442,17 +1475,20 @@ var Commands = Module("commands", {
 
         commands.add(["comc[lear]"],
             "Delete all user-defined commands",
-            function () {
-                commands.getUserCommands().forEach(function (cmd) { commands.removeUserCommand(cmd.name); });
+            function (args) {
+                args["-group"].clear();
             },
-            { argCount: "0" });
+            {
+                argCount: "0",
+                options: [contexts.GroupFlag("commands")]
+            });
 
         commands.add(["comp[letions]"],
             "List the completion results for a given command substring",
-            function (args) { completion.listCompleter("ex", args[0]); },
+            function (args) { modules.completion.listCompleter("ex", args[0]); },
             {
                 argCount: "1",
-                completer: function (context, args) completion.ex(context),
+                completer: function (context, args) modules.completion.ex(context),
                 literal: 0
             });
 
@@ -1461,13 +1497,14 @@ var Commands = Module("commands", {
             function (args) {
                 let name = args[0];
 
-                if (commands.get(name))
-                    commands.removeUserCommand(name);
+                if (args["-group"].get(name))
+                    args["-group"].remove(name);
                 else
                     dactyl.echoerr("E184: No such user-defined command: " + name);
             }, {
                 argCount: "1",
-                completer: function (context) completion.userCommand(context)
+                completer: function (context, args) modules.completion.userCommand(context, args["-group"]),
+                options: [contexts.GroupFlag("commands")]
             });
 
         dactyl.addUsageCommand({
@@ -1491,22 +1528,29 @@ var Commands = Module("commands", {
             "Yank the output of the given command to the clipboard",
             function (args) {
                 let cmd = /^:/.test(args[0]) ? args[0] : ":echo " + args[0];
-                let res = commandline.withOutputToString(commands.execute, commands, cmd);
+
+                let res = modules.commandline.withOutputToString(commands.execute, commands, cmd);
+
                 dactyl.clipboardWrite(res);
+
                 let lines = res.split("\n").length;
                 dactyl.echomsg("Yanked " + lines + " line" + (lines == 1 ? "" : "s"));
             },
             {
-                completer: function (context) completion[/^:/.test(context.filter) ? "ex" : "javascript"](context),
+                completer: function (context) modules.completion[/^:/.test(context.filter) ? "ex" : "javascript"](context),
                 literal: 0
             });
     },
-    javascript: function () {
+    javascript: function (dactyl, modules, window) {
+        const { JavaScript, commands } = modules;
+
         JavaScript.setCompleter([commands.user.get, commands.user.remove],
-                                [function () ([c.name, c.description] for (c in this))]);
+                                [function () [[c.name, c.description] for (c in this)]]);
     },
-    mappings: function () {
-        mappings.add(config.browserModes,
+    mappings: function (dactyl, modules, window) {
+        const { commands, mappings, modes } = modules;
+
+        mappings.add([modes.COMMAND],
             ["@:"], "Repeat the last Ex command",
             function (args) {
                 if (commands.repeat) {
@@ -1554,4 +1598,8 @@ var Commands = Module("commands", {
     };
 })();
 
-// vim: set fdm=marker sw=4 ts=4 et:
+endModule();
+
+} catch(e){ if (!e.stack) e = Error(e); dump(e.fileName+":"+e.lineNumber+": "+e+"\n" + e.stack); }
+
+// vim: set fdm=marker sw=4 ts=4 et ft=javascript:
diff --git a/common/modules/completion.jsm b/common/modules/completion.jsm
index 9b177586..3374ec2d 100644
--- a/common/modules/completion.jsm
+++ b/common/modules/completion.jsm
@@ -42,9 +42,11 @@ var CompletionContext = Class("CompletionContext", {
             let parent = editor;
             name = parent.name + "/" + name;
 
-            this.autoComplete = this.options.get("autocomplete").getKey(name);
-            this.sortResults  = this.options.get("wildsort").getKey(name);
-            this.wildcase     = this.options.get("wildcase").getKey(name);
+            if (this.options) {
+                this.autoComplete = this.options.get("autocomplete").getKey(name);
+                this.sortResults  = this.options.get("wildsort").getKey(name);
+                this.wildcase     = this.options.get("wildcase").getKey(name);
+            }
 
             this.contexts = parent.contexts;
             if (name in this.contexts)
@@ -448,7 +450,7 @@ var CompletionContext = Class("CompletionContext", {
         let self = this;
         delete this._substrings;
 
-        if (!this.forceAnchored)
+        if (!this.forceAnchored && this.options)
             this.anchored = this.options.get("wildanchor").getKey(this.name, this.anchored);
 
         // Item matchers
diff --git a/common/modules/io.jsm b/common/modules/io.jsm
index ee1f8dbe..bb52400c 100644
--- a/common/modules/io.jsm
+++ b/common/modules/io.jsm
@@ -748,16 +748,17 @@ unlet s:cpo_save
                     return lines.map(function (l) l.join("")).join("\n").replace(/\s+\n/gm, "\n");
                 }
 
+                const { commands, options } = modules;
                 file.write(template({
                     name: config.name,
                     autocommands: wrap("syn keyword " + config.name + "AutoEvent ",
                                        keys(config.autocommands)),
                     commands: wrap("syn keyword " + config.name + "Command ",
-                                  array(c.specs for (c in commands)).flatten()),
+                                  array(c.specs for (c in commands.iterator())).flatten()),
                     options: wrap("syn keyword " + config.name + "Option ",
-                                  array(o.names for (o in modules.options) if (o.type != "boolean")).flatten()),
+                                  array(o.names for (o in options) if (o.type != "boolean")).flatten()),
                     toggleoptions: wrap("let s:toggleOptions = [",
-                                        array(o.realNames for (o in modules.options) if (o.type == "boolean"))
+                                        array(o.realNames for (o in options) if (o.type == "boolean"))
                                             .flatten().map(String.quote),
                                         ", ") + "]"
                 }));
diff --git a/common/content/options.js b/common/modules/options.jsm
similarity index 84%
rename from common/content/options.js
rename to common/modules/options.jsm
index 67a4e3ec..a6d37d1e 100644
--- a/common/content/options.js
+++ b/common/modules/options.jsm
@@ -6,6 +6,16 @@
 // given in the LICENSE.txt file included with this file.
 "use strict";
 
+try {
+
+Components.utils.import("resource://dactyl/bootstrap.jsm");
+defineModule("options", {
+    exports: ["Option", "Options", "ValueError", "options"],
+    require: ["storage"],
+    use: ["commands", "completion", "prefs", "services", "template", "util"]
+}, this);
+
+
 /** @scope modules */
 
 let ValueError = Class("ValueError", ErrorBase);
@@ -83,7 +93,7 @@ var Option = Class("Option", {
     get helpTag() "'" + this.name + "'",
 
     initValue: function () {
-        dactyl.trapErrors(function () this.value = this.value, this);
+        util.trapErrors(function () this.value = this.value, this);
     },
 
     get isDefault() this.stringValue === this.stringDefaultValue,
@@ -127,13 +137,15 @@ var Option = Class("Option", {
 
         let values;
 
-        if (dactyl.has("tabs") && (scope & Option.SCOPE_LOCAL))
+        /*
+        if (config.has("tabs") && (scope & Option.SCOPE_LOCAL))
             values = tabs.options[this.name];
+         */
         if ((scope & Option.SCOPE_GLOBAL) && (values == undefined))
             values = this.globalValue;
 
         if (this.getter)
-            return dactyl.trapErrors(this.getter, this, values);
+            return util.trapErrors(this.getter, this, values);
 
         return values;
     },
@@ -151,19 +163,21 @@ var Option = Class("Option", {
             return;
 
         if (this.setter)
-            newValues = dactyl.trapErrors(this.setter, this, newValues);
+            newValues = this.modules.dactyl.trapErrors(this.setter, this, newValues);
         if (newValues === undefined)
             return;
 
-        if (dactyl.has("tabs") && (scope & Option.SCOPE_LOCAL))
+        /*
+        if (config.has("tabs") && (scope & Option.SCOPE_LOCAL))
             tabs.options[this.name] = newValues;
+        */
         if ((scope & Option.SCOPE_GLOBAL) && !skipGlobal)
             this.globalValue = newValues;
 
         this.hasChanged = true;
         this.setFrom = null;
 
-        dactyl.triggerObserver("options." + this.name, newValues);
+        // dactyl.triggerObserver("options." + this.name, newValues);
     },
 
     getValues: deprecated("Option#get", "get"),
@@ -239,7 +253,7 @@ var Option = Class("Option", {
         }
         catch (e) {
             if (!(e instanceof ValueError))
-                dactyl.reportError(e);
+                util.reportError(e);
             return this.invalidArgument(str || this.stringify(values), operator) + ": " + e.message;
         }
 
@@ -480,6 +494,7 @@ var Option = Class("Option", {
         Option._splitAt = 0;
         return arg;
     },
+
     splitList: function (value, keepQuotes) {
         let res = [];
         Option._splitAt = 0;
@@ -495,6 +510,7 @@ var Option = Class("Option", {
         }
         return res;
     },
+
     quote: function quote(str, re)
         Commands.quoteArg[/[\s|"'\\,]|^$/.test(str) || re && re.test && re.test(str)
             ? (/[\b\f\n\r\t]/.test(str) ? '"' : "'")
@@ -514,8 +530,8 @@ var Option = Class("Option", {
                 values = values[(values.indexOf(String(this.value)) + 1) % values.length];
 
             let value = parseInt(values);
-            dactyl.assert(Number(values) % 1 == 0,
-                          "E521: Number required after =: " + this.name + "=" + values);
+            util.assert(Number(values) % 1 == 0,
+                        "E521: Number required after =: " + this.name + "=" + values);
 
             switch (operator) {
             case "+":
@@ -627,7 +643,7 @@ var Option = Class("Option", {
     },
 
     validateXPath: function (values) {
-        let evaluator = XPathEvaluator();
+        let evaluator = services.XPathEvaluator();
         return this.testValues(values,
             function (value) evaluator.createExpression(value, util.evaluateXPath.resolver));
     }
@@ -637,73 +653,124 @@ var Option = Class("Option", {
  * @instance options
  */
 var Options = Module("options", {
-    init: function () {
-        this.needInit = [];
-        this._options = [];
-        this._optionMap = {};
+    Local: function (dactyl, modules, window) let ({ contexts } = modules) ({
+        init: function init() {
+            const self = this;
+            this.needInit = [];
+            this._options = [];
+            this._optionMap = {};
+            this.Option = Class("Option", Option, { modules: modules });
 
-        storage.newMap("options", { store: false });
-        storage.addObserver("options", function optionObserver(key, event, option) {
-            // Trigger any setters.
-            let opt = options.get(option);
-            if (event == "change" && opt)
-                opt.set(opt.globalValue, Option.SCOPE_GLOBAL, true);
-        }, window);
-    },
+            storage.newMap("options", { store: false });
+            storage.addObserver("options", function optionObserver(key, event, option) {
+                // Trigger any setters.
+                let opt = self.get(option);
+                if (event == "change" && opt)
+                    opt.set(opt.globalValue, Option.SCOPE_GLOBAL, true);
+            }, window);
+        },
 
-    cleanup: function cleanup() {
-        for (let opt in this)
-            if (opt.cleanupValue != null)
-                opt.value = opt.parse(opt.cleanupValue);
-    },
+        dactyl: dactyl,
+
+        /**
+         * Lists all options in *scope* or only those with changed values if
+         * *onlyNonDefault* is specified.
+         *
+         * @param {function(Option)} filter Limit the list
+         * @param {number} scope Only list options in this scope (see
+         *     {@link Option#scope}).
+         */
+        list: function (filter, scope) {
+            if (!scope)
+                scope = Option.SCOPE_BOTH;
+
+            function opts(opt) {
+                for (let opt in Iterator(options)) {
+                    let option = {
+                        __proto__: opt,
+                        isDefault: opt.isDefault,
+                        default:   opt.stringDefaultValue,
+                        pre:       "\u00a0\u00a0", // Unicode nonbreaking space.
+                        value:     <></>
+                    };
+
+                    if (filter && !filter(opt))
+                        continue;
+                    if (!(opt.scope & scope))
+                        continue;
+
+                    if (opt.type == "boolean") {
+                        if (!opt.value)
+                            option.pre = "no";
+                        option.default = (opt.defaultValue ? "" : "no") + opt.name;
+                    }
+                    else if (isArray(opt.value))
+                        option.value = <>={template.map(opt.value, function (v) template.highlight(String(v)), <>,<span style="width: 0; display: inline-block"> </span></>)}</>;
+                    else
+                        option.value = <>={template.highlight(opt.stringValue)}</>;
+                    yield option;
+                }
+            };
+
+            modules.commandline.commandOutput(template.options("Options", opts(), options["verbose"] > 0));
+        },
+
+        cleanup: function cleanup() {
+            for (let opt in this)
+                if (opt.cleanupValue != null)
+                    opt.value = opt.parse(opt.cleanupValue);
+        },
+
+        /**
+         * Adds a new option.
+         *
+         * @param {string[]} names All names for the option.
+         * @param {string} description A description of the option.
+         * @param {string} type The option type (see {@link Option#type}).
+         * @param {value} defaultValue The option's default value.
+         * @param {Object} extra An optional extra configuration hash (see
+         *     {@link Map#extraInfo}).
+         * @optional
+         */
+        add: function (names, description, type, defaultValue, extraInfo) {
+            const self = this;
+
+            if (!extraInfo)
+                extraInfo = {};
+
+            extraInfo.definedAt = contexts.getCaller(Components.stack.caller);
+
+            let name = names[0];
+            if (name in this._optionMap) {
+                this.dactyl.log("Warning: " + name.quote() + " already exists: replacing existing option.", 1);
+                this.remove(name);
+            }
+
+            let closure = function () self._optionMap[name];
+
+            memoize(this._optionMap, name, function () self.Option(names, description, type, defaultValue, extraInfo));
+            for (let alias in values(names.slice(1)))
+                memoize(this._optionMap, alias, closure);
+
+            if (extraInfo.setter && (!extraInfo.scope || extraInfo.scope & Option.SCOPE_GLOBAL))
+                if (this.dactyl.initialized)
+                    closure().initValue();
+                else
+                    memoize(this.needInit, this.needInit.length, closure);
+
+            this._floptions = (this._floptions || []).concat(name);
+            memoize(this._options, this._options.length, closure);
+
+            // quickly access options with options["wildmode"]:
+            this.__defineGetter__(name, function () this._optionMap[name].value);
+            this.__defineSetter__(name, function (value) { this._optionMap[name].value = value; });
+        }
+    }),
 
     /** @property {Iterator(Option)} @private */
     __iterator__: function ()
         values(this._options.sort(function (a, b) String.localeCompare(a.name, b.name))),
 
-    /**
-     * Adds a new option.
-     *
-     * @param {string[]} names All names for the option.
-     * @param {string} description A description of the option.
-     * @param {string} type The option type (see {@link Option#type}).
-     * @param {value} defaultValue The option's default value.
-     * @param {Object} extra An optional extra configuration hash (see
-     *     {@link Map#extraInfo}).
-     * @optional
-     */
-    add: function (names, description, type, defaultValue, extraInfo) {
-        if (!extraInfo)
-            extraInfo = {};
-
-        extraInfo.definedAt = Commands.getCaller(Components.stack.caller);
-
-        let name = names[0];
-        if (name in this._optionMap) {
-            dactyl.log("Warning: " + name.quote() + " already exists: replacing existing option.", 1);
-            this.remove(name);
-        }
-
-        let closure = function () options._optionMap[name];
-
-        memoize(this._optionMap, name, function () Option(names, description, type, defaultValue, extraInfo));
-        for (let alias in values(names.slice(1)))
-            memoize(this._optionMap, alias, closure);
-
-        if (extraInfo.setter && (!extraInfo.scope || extraInfo.scope & Option.SCOPE_GLOBAL))
-            if (dactyl.initialized)
-                closure().initValue();
-            else
-                memoize(this.needInit, this.needInit.length, closure);
-
-        this._floptions = (this._floptions || []).concat(name);
-        memoize(this._options, this._options.length, closure);
-
-        // quickly access options with options["wildmode"]:
-        this.__defineGetter__(name, function () this._optionMap[name].value);
-        this.__defineSetter__(name, function (value) { this._optionMap[name].value = value; });
-    },
-
     allPrefs: deprecated("prefs.getNames", function allPrefs() prefs.getNames.apply(prefs, arguments)),
     getPref: deprecated("prefs.get", function getPref() prefs.get.apply(prefs, arguments)),
     invertPref: deprecated("prefs.invert", function invertPref() prefs.invert.apply(prefs, arguments)),
@@ -734,49 +801,6 @@ var Options = Module("options", {
         return null;
     },
 
-    /**
-     * Lists all options in *scope* or only those with changed values if
-     * *onlyNonDefault* is specified.
-     *
-     * @param {function(Option)} filter Limit the list
-     * @param {number} scope Only list options in this scope (see
-     *     {@link Option#scope}).
-     */
-    list: function (filter, scope) {
-        if (!scope)
-            scope = Option.SCOPE_BOTH;
-
-        function opts(opt) {
-            for (let opt in Iterator(options)) {
-                let option = {
-                    __proto__: opt,
-                    isDefault: opt.isDefault,
-                    default:   opt.stringDefaultValue,
-                    pre:       "\u00a0\u00a0", // Unicode nonbreaking space.
-                    value:     <></>
-                };
-
-                if (filter && !filter(opt))
-                    continue;
-                if (!(opt.scope & scope))
-                    continue;
-
-                if (opt.type == "boolean") {
-                    if (!opt.value)
-                        option.pre = "no";
-                    option.default = (opt.defaultValue ? "" : "no") + opt.name;
-                }
-                else if (isArray(opt.value))
-                    option.value = <>={template.map(opt.value, function (v) template.highlight(String(v)), <>,<span style="width: 0; display: inline-block"> </span></>)}</>;
-                else
-                    option.value = <>={template.highlight(opt.stringValue)}</>;
-                yield option;
-            }
-        };
-
-        commandline.commandOutput(template.options("Options", opts(), options["verbose"] > 0));
-    },
-
     /**
      * Parses a :set command's argument string.
      *
@@ -801,7 +825,7 @@ var Options = Module("options", {
         }
 
         if (matches) {
-            ret.option = options.get(ret.name, ret.scope);
+            ret.option = this.get(ret.name, ret.scope);
             if (!ret.option && (ret.option = options.get(prefix + ret.name, ret.scope))) {
                 ret.name = prefix + ret.name;
                 prefix = "";
@@ -849,7 +873,9 @@ var Options = Module("options", {
     get store() storage.options
 }, {
 }, {
-    commands: function () {
+    commands: function initCommands(dactyl, modules, window) {
+        const { commands, contexts, options } = modules;
+
         let args = {
             getMode: function (args) findMode(args["-mode"]),
             iterate: function (args) {
@@ -916,7 +942,7 @@ var Options = Module("options", {
                     }
 
                     if (name == "all" && reset)
-                        commandline.input("Warning: Resetting all preferences may make " + config.host + " unusable. Continue (yes/[no]): ",
+                        modules.commandline.input("Warning: Resetting all preferences may make " + config.host + " unusable. Continue (yes/[no]): ",
                             function (resp) {
                                 if (resp == "yes")
                                     for (let pref in values(prefs.getNames()))
@@ -946,22 +972,21 @@ var Options = Module("options", {
                         prefs.set(name, value);
                     }
                     else
-                        commandline.commandOutput(prefs.list(onlyNonDefault, name));
+                        modules.commandline.commandOutput(prefs.list(onlyNonDefault, name));
                     return;
                 }
 
-                let opt = options.parseOpt(arg, modifiers);
-                dactyl.assert(opt, "Error parsing :set command: " + arg);
+                let opt = modules.options.parseOpt(arg, modifiers);
+                util.assert(opt, "Error parsing :set command: " + arg);
 
                 let option = opt.option;
-                dactyl.assert(option != null || opt.all,
-                    "E518: Unknown option: " + opt.name);
+                util.assert(option != null || opt.all, "E518: Unknown option: " + opt.name);
 
                 // reset a variable to its default value
                 if (opt.reset) {
                     flushList();
                     if (opt.all) {
-                        for (let option in options)
+                        for (let option in modules.options)
                             option.reset();
                     }
                     else {
@@ -975,7 +1000,7 @@ var Options = Module("options", {
                 else {
                     flushList();
                     if (opt.option.type === "boolean") {
-                        dactyl.assert(!opt.valueGiven, "E474: Invalid argument: " + arg);
+                        util.assert(!opt.valueGiven, "E474: Invalid argument: " + arg);
                         opt.values = !opt.unsetBoolean;
                     }
                     else if (/^(string|number)$/.test(opt.option.type) && opt.invert)
@@ -989,7 +1014,7 @@ var Options = Module("options", {
                     }
                     if (res)
                         dactyl.echoerr(res);
-                    option.setFrom = Commands.getCaller(null);
+                    option.setFrom = contexts.getCaller(null);
                 }
             }
             flushList();
@@ -1014,7 +1039,7 @@ var Options = Module("options", {
                 return completion.preference(context);
             }
 
-            let opt = options.parseOpt(filter, modifiers);
+            let opt = modules.options.parseOpt(filter, modifiers);
             let prefix = opt.prefix;
 
             context.highlight();
@@ -1055,7 +1080,7 @@ var Options = Module("options", {
             }
 
             let optcontext = context.fork("values");
-            completion.optionValue(optcontext, opt.name, opt.operator);
+            modules.completion.optionValue(optcontext, opt.name, opt.operator);
 
             // Fill in the current values if we're removing
             if (opt.operator == "-" && isArray(opt.values)) {
@@ -1065,7 +1090,7 @@ var Options = Module("options", {
                 context.maxItems = optcontext.maxItems;
 
                 context.filters.push(function (i) !set.has(have, i.text));
-                completion.optionValue(context, opt.name, opt.operator, null,
+                modules.completion.optionValue(context, opt.name, opt.operator, null,
                                        function (context) {
                                            context.generate = function () option.value.map(function (o) [o, ""]);
                                        });
@@ -1108,10 +1133,10 @@ var Options = Module("options", {
                     let [, scope, name, op, expr] = matches;
                     let fullName = (scope || "") + name;
 
-                    dactyl.assert(scope == "g:" || scope == null,
-                        "E461: Illegal variable name: " + scope + name);
-                    dactyl.assert(set.has(globalVariables, name) || (expr && !op),
-                        "E121: Undefined variable: " + fullName);
+                    util.assert(scope == "g:" || scope == null,
+                                "E461: Illegal variable name: " + scope + name);
+                    util.assert(set.has(globalVariables, name) || (expr && !op),
+                                "E121: Undefined variable: " + fullName);
 
                     if (!expr)
                         dactyl.echo(fullName + "\t\t" + fmt(globalVariables[name]));
@@ -1120,7 +1145,7 @@ var Options = Module("options", {
                             var newValue = dactyl.userEval(expr);
                         }
                         catch (e) {}
-                        dactyl.assert(newValue !== undefined,
+                        util.assert(newValue !== undefined,
                             "E15: Invalid expression: " + expr);
 
                         let value = newValue;
@@ -1167,7 +1192,7 @@ var Options = Module("options", {
                             literalArg: [opt.type == "boolean" ? (opt.value ? "" : "no") + opt.name
                                                                : opt.name + "=" + opt.stringValue]
                         }
-                        for (opt in options)
+                        for (opt in modules.options)
                         if (!opt.getter && !opt.isDefault && (opt.scope & Option.SCOPE_GLOBAL))
                     ]
                 }
@@ -1182,18 +1207,18 @@ var Options = Module("options", {
                     completer: setCompleter,
                     domains: function (args) array.flatten(args.map(function (spec) {
                         try {
-                            let opt = options.parseOpt(spec);
+                            let opt = modules.options.parseOpt(spec);
                             if (opt.option && opt.option.domains)
                                 return opt.option.domains(opt.values);
                         }
                         catch (e) {
-                            dactyl.reportError(e);
+                            util.reportError(e);
                         }
                         return [];
                     })),
                     keepQuotes: true,
                     privateData: function (args) args.some(function (spec) {
-                        let opt = options.parseOpt(spec);
+                        let opt = modules.options.parseOpt(spec);
                         return opt.option && opt.option.privateData &&
                             (!callable(opt.option.privateData) ||
                              opt.option.privateData(opt.values));
@@ -1223,12 +1248,14 @@ var Options = Module("options", {
                 deprecated: "the options system"
             });
     },
-    completion: function () {
+    completion: function initCompletion(dactyl, modules, window) {
+        const { completion } = modules;
+
         completion.option = function option(context, scope, prefix) {
             context.title = ["Option"];
             context.keys = { text: "names", description: "description" };
             context.anchored = false;
-            context.completions = options;
+            context.completions = modules.options;
             if (prefix == "inv")
                 context.keys.text = function (opt)
                     opt.type == "boolean" || isArray(opt.value) ? opt.names.map(function (n) "inv" + n)
@@ -1238,7 +1265,7 @@ var Options = Module("options", {
         };
 
         completion.optionValue = function (context, name, op, curValue, completer) {
-            let opt = options.get(name);
+            let opt = modules.options.get(name);
             completer = completer || opt.completer;
             if (!completer || !opt)
                 return;
@@ -1301,15 +1328,18 @@ var Options = Module("options", {
                 context.completions = res;
         };
     },
-    javascript: function () {
+    javascript: function initJavascript(dactyl, modules, window) {
+        const { options, JavaScript } = modules;
         JavaScript.setCompleter(options.get, [function () ([o.name, o.description] for (o in options))]);
     },
-    sanitizer: function () {
+    sanitizer: function initSanitizer(dactyl, modules, window) {
+        const { sanitizer } = modules;
+
         sanitizer.addItem("options", {
             description: "Options containing hostname data",
             action: function (timespan, host) {
                 if (host)
-                    for (let opt in values(options._options))
+                    for (let opt in values(modules.options._options))
                         if (timespan.contains(opt.lastSet * 1000) && opt.domains)
                             try {
                                 opt.value = opt.filterDomain(host, opt.value);
@@ -1319,12 +1349,12 @@ var Options = Module("options", {
                             }
             },
             privateEnter: function () {
-                for (let opt in values(options._options))
+                for (let opt in values(modules.options._options))
                     if (opt.privateData && (!callable(opt.privateData) || opt.privateData(opt.value)))
                         opt.oldValue = opt.value;
             },
             privateLeave: function () {
-                for (let opt in values(options._options))
+                for (let opt in values(modules.options._options))
                     if (opt.oldValue != null) {
                         opt.value = opt.oldValue;
                         opt.oldValue = null;
@@ -1334,4 +1364,8 @@ var Options = Module("options", {
     }
 });
 
-// vim: set fdm=marker sw=4 ts=4 et:
+endModule();
+
+} catch(e){ if (!e.stack) e = Error(e); dump(e.fileName+":"+e.lineNumber+": "+e+"\n" + e.stack); }
+
+// vim: set fdm=marker sw=4 ts=4 et ft=javascript:
diff --git a/common/modules/overlay.jsm b/common/modules/overlay.jsm
index af88c6be..c878c724 100644
--- a/common/modules/overlay.jsm
+++ b/common/modules/overlay.jsm
@@ -154,6 +154,7 @@ var Overlay = Module("Overlay", {
                 defineModule.time("load", null, function _load() {
                     ["addons",
                      "base",
+                     "commands",
                      "completion",
                      "config",
                      "downloads",
@@ -161,6 +162,7 @@ var Overlay = Module("Overlay", {
                      "highlight",
                      "io",
                      "javascript",
+                     "options",
                      "overlay",
                      "prefs",
                      "services",
@@ -177,14 +179,12 @@ var Overlay = Module("Overlay", {
                      "abbreviations",
                      "autocommands",
                      "buffer",
-                     "commands",
                      "editor",
                      "events",
                      "hints",
                      "mappings",
                      "marks",
                      "mow",
-                     "options",
                      "statusline"
                      ].forEach(function (name) defineModule.time("load", name, modules.load, modules, name));
 
@@ -325,6 +325,8 @@ var Overlay = Module("Overlay", {
     }
 });
 
+endModule();
+
 } catch(e){ if (!e.stack) e = Error(e); dump(e.fileName+":"+e.lineNumber+": "+e+"\n" + e.stack); }
 
 // vim: set fdm=marker sw=4 ts=4 et ft=javascript:
diff --git a/common/modules/services.jsm b/common/modules/services.jsm
index 6c38529b..7b31a422 100644
--- a/common/modules/services.jsm
+++ b/common/modules/services.jsm
@@ -84,6 +84,7 @@ var Services = Module("Services", {
         this.addClass("Timer",        "@mozilla.org/timer;1",                      Ci.nsITimer, "initWithCallback");
         this.addClass("StreamCopier", "@mozilla.org/network/async-stream-copier;1",Ci.nsIAsyncStreamCopier, "init");
         this.addClass("Xmlhttp",      "@mozilla.org/xmlextras/xmlhttprequest;1",   Ci.nsIXMLHttpRequest);
+        this.addClass("XPathEvaluator", "@mozilla.org/dom/xpath-evaluator;1",      Ci.nsIDOMXPathEvaluator);
         this.addClass("ZipReader",    "@mozilla.org/libjar/zip-reader;1",          Ci.nsIZipReader, "open");
         this.addClass("ZipWriter",    "@mozilla.org/zipwriter;1",                  Ci.nsIZipWriter);
     },
diff --git a/common/modules/styles.jsm b/common/modules/styles.jsm
index 921e11bc..245feccd 100644
--- a/common/modules/styles.jsm
+++ b/common/modules/styles.jsm
@@ -623,6 +623,9 @@ var Styles = Module("Styles", {
                     this.hive.addRef(this);
                 },
 
+                get names() this.hive.names,
+                get sheets() this.hive.sheets,
+
                 __noSuchMethod__: function __noSuchMethod__(meth, args) {
                     return this.hive[meth].apply(this.hive, args);
                 },
diff --git a/common/modules/util.jsm b/common/modules/util.jsm
index b2d62ad4..18f7e83a 100644
--- a/common/modules/util.jsm
+++ b/common/modules/util.jsm
@@ -13,7 +13,7 @@ Components.utils.import("resource://dactyl/bootstrap.jsm");
 defineModule("util", {
     exports: ["frag", "FailedAssertion", "Math", "NS", "Point", "Util", "XBL", "XHTML", "XUL", "util"],
     require: ["services"],
-    use: ["config", "highlight", "storage", "template"]
+    use: ["commands", "config", "highlight", "storage", "template"]
 }, this);
 
 var XBL = Namespace("xbl", "http://www.mozilla.org/xbl");
@@ -22,13 +22,6 @@ var XUL = Namespace("xul", "http://www.mozilla.org/keymaster/gatekeeper/there.is
 var NS = Namespace("dactyl", "http://vimperator.org/namespaces/liberator");
 default xml namespace = XHTML;
 
-memoize(this, "Commands", function () {
-    // FIXME
-    let obj = { Module: Class };
-    JSMLoader.loadSubScript("resource://dactyl-content/commands.js", obj);
-    return obj.Commands;
-});
-
 var FailedAssertion = Class("FailedAssertion", ErrorBase);
 var Point = Struct("x", "y");
 
diff --git a/common/tests/functional/dactyl.jsm b/common/tests/functional/dactyl.jsm
index b32b7313..f7ce56ab 100644
--- a/common/tests/functional/dactyl.jsm
+++ b/common/tests/functional/dactyl.jsm
@@ -64,7 +64,7 @@ function Controller(controller) {
     }
     this.errors = [];
     this._countError = function countError(message, highlight) {
-        if (/\bErrorMsg\b/.test(highlight))
+        if (/\b(Error|Warning)Msg\b/.test(highlight))
             self.errors.push(String(message));
     }
     this.modules.dactyl.registerObserver("beep", this._countBeep);
diff --git a/common/tests/functional/testCommands.js b/common/tests/functional/testCommands.js
index 618b688f..1d439861 100644
--- a/common/tests/functional/testCommands.js
+++ b/common/tests/functional/testCommands.js
@@ -122,7 +122,17 @@ var tests = {
         singleOutput: ["", "foobar"],
         noOutput: ["foo bar", "-js bar baz"],
         multiOutput: [""],
-        error: ["foo bar", "-js bar baz"]
+        error: [
+            "foo bar",
+            "-js bar baz",
+            "-group=builtin baz quux",
+            "! -group=builtin baz quux",
+        ],
+        completions: [
+            ["", hasItems],
+            ["-group=", hasItems],
+            ["-group=user ", hasItems]
+        ]
     },
     comclear: {
         noOutput: [""]
@@ -140,6 +150,11 @@ var tests = {
     delcommand: [
         {
             init: ["comclear", "command foo bar"],
+            completions: [
+                ["", hasItems],
+                ["-group=", hasItems],
+                ["-group=user ", hasItems]
+            ],
             noOutput: ["foo"]
         },
         {
@@ -152,7 +167,6 @@ var tests = {
         noOutput: ["x"],
         completions: ["", "x"]
     },
-    delmapgroup: {}, // Skip for now
     get delmarks() this.delmacros,
     get delqmarks() this.delmacros,
     delstyle: {
@@ -233,6 +247,25 @@ var tests = {
     finish: { noOutput: [""] },
     forward: { noOutput: [""] },
     frameonly: { noOutput: [""] },
+    delgroup: {
+        error: ["builtin"],
+        completions: [""]
+    },
+    group: {
+        multiOutput: [""],
+        noOutput: [
+            "foo -d='foo group' -nopersist -l 'bar.com','http://bar/*','http://bar','^http:'",
+            "! foo -d='foo group' -nopersist -l 'bar.com','http://bar/*','http://bar','^http:'",
+            "foo",
+            "user"
+        ],
+        error: ["builtin"],
+        completions: [
+            "",
+            "foo "
+        ],
+        cleanup: ["delmapgroup foo"]
+    },
     hardcopy: {}, // Skip for now
     help: {
         noOutput: ["", "intro"],
@@ -318,7 +351,8 @@ var tests = {
         ],
         error: [
             "-mode=some-nonexistent-mode <C-a> <C-a>",
-            "-gtroup=some-nonexistent-group <C-a> <C-a>"
+            "-group=some-nonexistent-group <C-a> <C-a>",
+            "-group=builtin <C-a> <C-a>"
         ],
         completions: [
             ["", hasItems],
@@ -333,25 +367,13 @@ var tests = {
     },
     mapclear: {
         noOutput: [""],
-        completions: [""]
-    },
-    mapgroup: {
-        multiOutput: [""],
-        noOutput: [
-            "foo -d='foo group' -nopersist 'bar.com,http://bar/*,http://bar,^http:'",
-            "! foo -d='foo group' -nopersist 'bar.com,http://bar/*,http://bar,^http:'",
-            "foo",
-            "user"
-        ],
         error: [
-            "some-nonexistent-group",
-            "foo -d='foo group' -nopersist 'bar.com,http://bar/*,http://bar,^http:'"
+            "-group=builtin"
         ],
         completions: [
             "",
-            "foo "
-        ],
-        cleanup: ["delmapgroup foo"]
+            "-group="
+        ]
     },
     mark: {
         error: ["", "#", "xy"],