diff --git a/Makefile.dryice.js b/Makefile.dryice.js
index a041f32b..aed33736 100755
--- a/Makefile.dryice.js
+++ b/Makefile.dryice.js
@@ -200,7 +200,6 @@ function demo(aceProject) {
         compat: false,
         name: "kitchen-sink",
         suffix: "-uncompressed.js",
-        modes: [],
         keybindings: []
     });
 }
diff --git a/demo/kitchen-sink/demo.js b/demo/kitchen-sink/demo.js
index f1b92b10..d3acd780 100644
--- a/demo/kitchen-sink/demo.js
+++ b/demo/kitchen-sink/demo.js
@@ -41,9 +41,9 @@
 define(function(require, exports, module) {
 
 require("ace/lib/fixoldbrowsers");
+require("ace/config").init(); 
 var env = {};
 
-var net = require("ace/lib/net");
 var event = require("ace/lib/event");
 var theme = require("ace/theme/textmate");
 var EditSession = require("ace/edit_session").EditSession;
@@ -61,6 +61,7 @@ var Doc = function(name, desc, file) {
     this.desc = desc;
     this.doc = new EditSession(file);
     this.doc.setMode(modesByName[name].mode);
+    this.doc.modeName = name;
     this.doc.setUndoManager(new UndoManager());
 };
 
@@ -71,13 +72,10 @@ var WrappedDoc = function(name, desc, file) {
     this.doc.setWrapLimitRange(80, 80);
 };
 
-var Mode = function(name, desc, clazz, extensions) {
+var Mode = function(name, desc, extensions) {
     this.name = name;
     this.desc = desc;
-    this.clazz = clazz;
-    this.mode = new clazz();
-    this.mode.name = name;
-
+    this.mode = "ace/mode/" + name;
     this.extRe = new RegExp("^.*\\.(" + extensions.join("|") + ")$", "g");
 };
 
@@ -85,48 +83,37 @@ Mode.prototype.supportsFile = function(filename) {
     return filename.match(this.extRe);
 };
 
-var themes = {};
-function loadTheme(name, callback) {
-    if (themes[name])
-        return callback();
-
-    themes[name] = 1;
-    var base = name.split("/").pop();
-    var fileName = "demo/kitchen-sink/theme-" + base + "-uncompressed.js";
-    net.loadScript(fileName, callback);
-}
-
 var modes = [
-    new Mode("c_cpp", "C/C++", require("ace/mode/c_cpp").Mode, ["c", "cpp", "cxx", "h", "hpp"]),
-    new Mode("clojure", "Clojure", require("ace/mode/clojure").Mode, ["clj"]),
-    new Mode("coffee", "CoffeeScript", require("ace/mode/coffee").Mode, ["coffee"]),
-    new Mode("coldfusion", "ColdFusion", require("ace/mode/coldfusion").Mode, ["cfm"]),
-    new Mode("csharp", "C#", require("ace/mode/csharp").Mode, ["cs"]),
-    new Mode("css", "CSS", require("ace/mode/css").Mode, ["css"]),
-    new Mode("groovy", "Groovy", require("ace/mode/groovy").Mode, ["groovy"]),
-    new Mode("haxe", "haXe", require("ace/mode/haxe").Mode, ["hx"]),
-    new Mode("html", "HTML", require("ace/mode/html").Mode, ["html", "htm"]),
-    new Mode("java", "Java", require("ace/mode/java").Mode, ["java"]),
-    new Mode("javascript", "JavaScript", require("ace/mode/javascript").Mode, ["js"]),
-    new Mode("json", "JSON", require("ace/mode/json").Mode, ["json"]),
-    new Mode("latex", "LaTeX", require("ace/mode/latex").Mode, ["tex"]),
-    new Mode("lua", "Lua", require("ace/mode/lua").Mode, ["lua"]),
-    new Mode("markdown", "Markdown", require("ace/mode/markdown").Mode, ["md", "markdown"]),
-    new Mode("ocaml", "OCaml", require("ace/mode/ocaml").Mode, ["ml", "mli"]),
-    new Mode("perl", "Perl", require("ace/mode/perl").Mode, ["pl", "pm"]),
-    new Mode("pgsql", "pgSQL",require("ace/mode/pgsql").Mode, ["pgsql", "sql"]),
-    new Mode("php", "PHP",require("ace/mode/php").Mode, ["php"]),
-    new Mode("powershell", "Powershell", require("ace/mode/powershell").Mode, ["ps1"]),
-    new Mode("python", "Python", require("ace/mode/python").Mode, ["py"]),
-    new Mode("scala", "Scala", require("ace/mode/scala").Mode, ["scala"]),
-    new Mode("scss", "SCSS", require("ace/mode/scss").Mode, ["scss"]),
-    new Mode("ruby", "Ruby", require("ace/mode/ruby").Mode, ["rb"]),
-    new Mode("sql", "SQL", require("ace/mode/sql").Mode, ["sql"]),
-    new Mode("svg", "SVG", require("ace/mode/svg").Mode, ["svg"]),
-    new Mode("text", "Text", require("ace/mode/text").Mode, ["txt"]),
-    new Mode("textile", "Textile", require("ace/mode/textile").Mode, ["textile"]),
-    new Mode("xml", "XML", require("ace/mode/xml").Mode, ["xml"]),
-    new Mode("sh", "SH", require("ace/mode/sh").Mode, ["sh"])
+    new Mode("c_cpp", "C/C++", ["c", "cpp", "cxx", "h", "hpp"]),
+    new Mode("clojure", "Clojure", ["clj"]),
+    new Mode("coffee", "CoffeeScript", ["coffee"]),
+    new Mode("coldfusion", "ColdFusion", ["cfm"]),
+    new Mode("csharp", "C#", ["cs"]),
+    new Mode("css", "CSS", ["css"]),
+    new Mode("groovy", "Groovy", ["groovy"]),
+    new Mode("haxe", "haXe", ["hx"]),
+    new Mode("html", "HTML", ["html", "htm"]),
+    new Mode("java", "Java", ["java"]),
+    new Mode("javascript", "JavaScript", ["js"]),
+    new Mode("json", "JSON", ["json"]),
+    new Mode("latex", "LaTeX", ["tex"]),
+    new Mode("lua", "Lua", ["lua"]),
+    new Mode("markdown", "Markdown", ["md", "markdown"]),
+    new Mode("ocaml", "OCaml", ["ml", "mli"]),
+    new Mode("perl", "Perl", ["pl", "pm"]),
+    new Mode("pgsql", "pgSQL", ["pgsql", "sql"]),
+    new Mode("php", "PHP", ["php"]),
+    new Mode("powershell", "Powershell", ["ps1"]),
+    new Mode("python", "Python", ["py"]),
+    new Mode("scala", "Scala", ["scala"]),
+    new Mode("scss", "SCSS", ["scss"]),
+    new Mode("ruby", "Ruby", ["rb"]),
+    new Mode("sql", "SQL", ["sql"]),
+    new Mode("svg", "SVG", ["svg"]),
+    new Mode("text", "Text", ["txt"]),
+    new Mode("textile", "Textile", ["textile"]),
+    new Mode("xml", "XML", ["xml"]),
+    new Mode("sh", "SH", ["sh"])
 ];
 
 modesByName = {};
@@ -337,7 +324,7 @@ function updateUIEditorOptions() {
     var session = editor.session;
 
     docEl.value = session.name;
-    modeEl.value = session.getMode().name || "text";
+    modeEl.value = session.modeName || "text";
 
     session.setFoldStyle(foldingEl.value);
 
@@ -361,20 +348,14 @@ function updateUIEditorOptions() {
 
 bindDropdown("mode", function(value) {
     env.editor.getSession().setMode(modesByName[value].mode || modesByName.text.mode);
+    env.editor.getSession().modeName = value;
 });
 
 bindDropdown("theme", function(value) {
     if (!value)
         return;
 
-    if (module.packaged) {
-        loadTheme(value, function() {
-            env.editor.setTheme(value);
-        });
-    }
-    else {
-        env.editor.setTheme(value);
-    }
+    env.editor.setTheme(value);
 });
 
 bindDropdown("keybinding", function(value) {
@@ -536,6 +517,7 @@ event.addListener(container, "drop", function(e) {
 
             modeEl.value = mode.name;
             env.editor.getSession().setMode(mode.mode);
+            env.editor.getSession().modeName = mode.name;
         };
         reader.readAsText(file);
     }
diff --git a/kitchen-sink.html b/kitchen-sink.html
index f721fc70..705fa3c5 100644
--- a/kitchen-sink.html
+++ b/kitchen-sink.html
@@ -212,7 +212,7 @@
 <!--DEVEL -->
   
 <!--PACKAGE
-  <script src="demo/kitchen-sink/kitchen-sink-uncompressed.js" data-ace-base="demo/kitchen-sink" type="text/javascript" charset="utf-8"></script>
+  <script src="demo/kitchen-sink/kitchen-sink-uncompressed.js" data-ace-suffix="-uncompressed.js" data-ace-base="demo/kitchen-sink" type="text/javascript" charset="utf-8"></script>
   <script type="text/javascript" charset="utf-8">
     require("kitchen-sink/demo");
   </script>
diff --git a/lib/ace/ace.js b/lib/ace/ace.js
index a450211f..04e342e6 100644
--- a/lib/ace/ace.js
+++ b/lib/ace/ace.js
@@ -49,6 +49,7 @@ var UndoManager = require("./undomanager").UndoManager;
 var Renderer = require("./virtual_renderer").VirtualRenderer;
 
 require("./worker/worker_client");
+require("./config").init();
 
 exports.edit = function(el) {
     if (typeof(el) == "string") {
diff --git a/lib/ace/config.js b/lib/ace/config.js
new file mode 100644
index 00000000..c8b0a015
--- /dev/null
+++ b/lib/ace/config.js
@@ -0,0 +1,128 @@
+/* vim:ts=4:sts=4:sw=4:
+ * ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is Ajax.org Code Editor (ACE).
+ *
+ * The Initial Developer of the Original Code is
+ * Ajax.org B.V.
+ * Portions created by the Initial Developer are Copyright (C) 2010
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *      Fabian Jakobs <fabian AT ajax DOT org>
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+define(function(require, exports, module) {
+"no use strict";
+
+var lang = require("./lib/lang");
+
+var global = (function() {
+    return this;
+})();
+
+var options = {
+    packaged: false,
+    workerPath: "",
+    modePath: "",
+    themePath: "",
+    suffix: ".js"
+};
+
+exports.get = function(key) {
+    if (!options.hasOwnProperty(key))
+        throw new Error("Unknown confik key: " + key);
+        
+    return options[key];
+};
+
+exports.set = function(key, value) {
+    if (!options.hasOwnProperty(key))
+        throw new Error("Unknown confik key: " + key);
+        
+    options[key] = value;
+};
+
+exports.all = function() {
+    return lang.copyObject(options);
+};
+
+exports.init = function() {
+    options.packaged = require.packaged || module.packaged || (global.define && define.packaged);
+
+    if (!global.document)
+        return "";
+
+    var scriptOptions = {};
+    var scriptUrl = "";
+    var suffix;
+    
+    var scripts = document.getElementsByTagName("script");
+    for (var i=0; i<scripts.length; i++) {
+        var script = scripts[i];
+
+        var src = script.src || script.getAttribute("src");
+        if (!src) {
+            continue;
+        }
+        
+        var attributes = script.attributes;
+        for (var j=0, l=attributes.length; j < l; j++) {
+            var attr = attributes[j];
+            if (attr.name.indexOf("data-ace-") === 0) {
+                scriptOptions[deHyphenate(attr.name.replace(/^data-ace-/, ""))] = attr.value;
+            }
+        }
+
+        var m = src.match(/^(?:(.*\/)ace\.js|(.*\/)ace((-uncompressed)?(-noconflict)?\.js))(?:\?|$)/);
+        if (m) {
+            scriptUrl = m[1] || m[2];
+            suffix = m[3];
+        }
+    }
+    
+    if (scriptUrl) {
+        scriptOptions.base = scriptOptions.base || scriptUrl;
+        scriptOptions.packaged = true;
+    }
+    
+    scriptOptions.suffix = scriptOptions.suffix || suffix;
+    scriptOptions.workerPath = scriptOptions.workerPath || scriptOptions.base;
+    scriptOptions.modePath = scriptOptions.modePath || scriptOptions.base;
+    scriptOptions.themePath = scriptOptions.themePath || scriptOptions.base;
+    delete scriptOptions.base;
+    
+    for (var key in scriptOptions)
+        if (typeof scriptOptions[key] !== "undefined")
+            exports.set(key, scriptOptions[key]);
+};
+
+function deHyphenate(str) {
+    return str.replace(/-(.)/g, function(m, m1) { return m1.toUpperCase(); });
+}
+
+});
\ No newline at end of file
diff --git a/lib/ace/edit_session.js b/lib/ace/edit_session.js
index 6aa21896..20ed7355 100644
--- a/lib/ace/edit_session.js
+++ b/lib/ace/edit_session.js
@@ -41,8 +41,10 @@
 define(function(require, exports, module) {
 "use strict";
 
+var config = require("./config");
 var oop = require("./lib/oop");
 var lang = require("./lib/lang");
+var net = require("./lib/net");
 var EventEmitter = require("./lib/event_emitter").EventEmitter;
 var Selection = require("./selection").Selection;
 var TextMode = require("./mode/text").Mode;
@@ -484,10 +486,61 @@ var EditSession = function(text, mode) {
         this._emit("tokenizerUpdate", e);
     };
 
+    this.$modes = {};
+    this._loadMode = function(mode, callback) {
+        if (this.$modes[mode])
+            return callback(this.$modes[mode]);
+        
+        var _self = this;
+        var module;
+        try {
+            module = require(mode);
+        } catch (e) {};
+        if (module)
+            return done(module);
+            
+        fetch(function() {
+            require([mode], done);
+        });
+        
+        function done(module) {
+            if (_self.$modes[mode])
+                return callback(_self.$modes[mode]);
+            
+            _self.$modes[mode] = new module.Mode();
+            callback(_self.$modes[mode]);
+        }
+
+        function fetch(callback) {
+            if (!config.get("packaged"))
+                return callback();
+                
+            var base = mode.split("/").pop();
+            var filename = config.get("modePath") + "/mode-" + base + config.get("suffix");
+            net.loadScript(filename, callback);
+        }
+    };
+
     this.$mode = null;
+    this.$origMode = null;
     this.setMode = function(mode) {
+        this.$origMode = mode;
+        
+        // load on demand
+        if (typeof mode === "string") {
+            var _self = this;
+            this._loadMode(mode, function(module) {
+                if (_self.$origMode !== mode)
+                    return;
+            
+                _self.setMode(module);
+            });
+            return;
+        }
+        
         if (this.$mode === mode) return;
         this.$mode = mode;
+        
 
         this.$stopWorker();
 
diff --git a/lib/ace/virtual_renderer.js b/lib/ace/virtual_renderer.js
index 0e6b9f7c..0ac360f5 100644
--- a/lib/ace/virtual_renderer.js
+++ b/lib/ace/virtual_renderer.js
@@ -45,6 +45,8 @@ var oop = require("./lib/oop");
 var dom = require("./lib/dom");
 var event = require("./lib/event");
 var useragent = require("./lib/useragent");
+var config = require("./config");
+var net = require("./lib/net");
 var GutterLayer = require("./layer/gutter").Gutter;
 var MarkerLayer = require("./layer/marker").Marker;
 var TextLayer = require("./layer/text").Text;
@@ -803,14 +805,36 @@ var VirtualRenderer = function(container, theme) {
         style.left = "-10000px";
     };
 
+    this._loadTheme = function(name, callback) {
+        if (!config.get("packaged"))
+            return callback();
+            
+        var base = name.split("/").pop();
+        var filename = config.get("themePath") + "/theme-" + base + config.get("suffix");
+        net.loadScript(filename, callback);
+    };
+
     this.setTheme = function(theme) {
         var _self = this;
 
         this.$themeValue = theme;
         if (!theme || typeof theme == "string") {
-            theme = theme || "ace/theme/textmate";
-            require([theme], function(theme) {
-                afterLoad(theme);
+            var moduleName = theme || "ace/theme/textmate";
+            
+            var module;
+            try {
+                module = require(moduleName);
+            } catch (e) {};
+            if (module)
+                return afterLoad(module);
+            
+            _self._loadTheme(moduleName, function() {
+                require([theme], function(module) {
+                    if (_self.$themeValue !== theme)
+                        return;
+
+                    afterLoad(module);
+                });
             });
         } else {
             afterLoad(theme);
diff --git a/lib/ace/worker/worker_client.js b/lib/ace/worker/worker_client.js
index 8948cb83..e0097d2d 100644
--- a/lib/ace/worker/worker_client.js
+++ b/lib/ace/worker/worker_client.js
@@ -40,14 +40,14 @@ define(function(require, exports, module) {
 
 var oop = require("../lib/oop");
 var EventEmitter = require("../lib/event_emitter").EventEmitter;
+var config = require("../config");
 
 var WorkerClient = function(topLevelNamespaces, packagedJs, mod, classname) {
 
     this.changeListener = this.changeListener.bind(this);
 
-    if (module.packaged) {
-        var base = this.$guessBasePath();
-        this.$worker = new Worker(base + packagedJs);
+    if (config.get("packaged")) {
+        this.$worker = new Worker(config.get("workerPath") + "/" + packagedJs);
     }
     else {
         var workerUrl = this.$normalizePath(require.nameToUrl("ace/worker/worker", null, "_"));
@@ -112,29 +112,6 @@ var WorkerClient = function(topLevelNamespaces, packagedJs, mod, classname) {
         return path;
     };
 
-    this.$guessBasePath = function() {
-        if (require.aceBaseUrl)
-            return require.aceBaseUrl;
-
-        var scripts = document.getElementsByTagName("script");
-        for (var i=0; i<scripts.length; i++) {
-            var script = scripts[i];
-
-            var base = script.getAttribute("data-ace-base");
-            if (base)
-                return base.replace(/\/*$/, "/");
-
-            var src = script.src || script.getAttribute("src");
-            if (!src) {
-                continue;
-            }
-            var m = src.match(/^(?:(.*\/)ace\.js|(.*\/)ace(-uncompressed)?(-noconflict)?\.js)(?:\?|$)/);
-            if (m)
-                return m[1] || m[2];
-        }
-        return "";
-    };
-
     this.terminate = function() {
         this._emit("terminate", {});
         this.$worker.terminate();