diff --git a/lib/ace/config.js b/lib/ace/config.js
index c617959d..4a7dc286 100644
--- a/lib/ace/config.js
+++ b/lib/ace/config.js
@@ -103,12 +103,12 @@ exports.loadModule = function(moduleName, onLoad) {
         module = require(moduleName);
     } catch (e) {};
     if (module)
-        return onLoad(module);
+        return onLoad && onLoad(module);
 
     var afterLoad = function() {
         require([moduleName], function(module) {
             exports._emit("load.module", {name: moduleName, module: module});
-            onLoad(module);
+            onLoad && onLoad(module);
         });
     };
 
diff --git a/lib/ace/ext/spellcheck.js b/lib/ace/ext/spellcheck.js
new file mode 100644
index 00000000..b3600e5f
--- /dev/null
+++ b/lib/ace/ext/spellcheck.js
@@ -0,0 +1,68 @@
+define(function(require, exports, module) {
+"use strict";
+var event = require("../lib/event");
+
+exports.contextMenuHandler = function(e){
+    var host = e.target;
+    var text = host.textInput.getElement();
+    if (!host.selection.isEmpty())
+        return;
+    var c = host.getCursorPosition();
+    var r = host.session.getWordRange(c.row, c.column);
+    var w = host.session.getTextRange(r);
+
+    host.session.tokenRe.lastIndex = 0;
+    if (!host.session.tokenRe.test(w))
+        return;
+    var PLACEHOLDER = "\x01\x01";
+    var value = w + " " + PLACEHOLDER;
+    text.value = value;
+    text.setSelectionRange(w.length + 1, w.length + 1);
+    text.setSelectionRange(0, 0);
+    
+    var afterKeydown = false;
+    event.addListener(text, "keydown", function onKeydown() {
+        event.removeListener(text, "keydown", onKeydown);
+        afterKeydown = true;
+    });
+
+    host.textInput.setInputHandler(function(newVal) {
+        console.log(newVal , value, text.selectionStart, text.selectionEnd)
+        if (newVal == value)
+            return '';
+        if (newVal.lastIndexOf(value, 0) === 0)
+            return newVal.slice(value.length);
+        if (newVal.substr(text.selectionEnd) == value)
+            return newVal.slice(0, -value.length);
+        if (newVal.slice(-2) == PLACEHOLDER) {
+            var val = newVal.slice(0, -2);
+            if (val.slice(-1) == " ") {
+                if (afterKeydown)
+                    return val.substring(0, text.selectionEnd);
+                val = val.slice(0, -1);
+                host.session.replace(r, val);
+                return "";
+            }
+        }
+        
+        return newVal;
+    });
+};
+// todo support highlighting with typo.js
+var Editor = require("../editor").Editor;
+require("../config").defineOptions(Editor.prototype, "editor", {
+    spellcheck: {
+        set: function(val) {
+            var text = this.textInput.getElement();
+            text.spellcheck = !!val;
+            if (!val)
+                this.removeListener("nativecontextmenu", exports.contextMenuHandler);
+            else
+                this.on("nativecontextmenu", exports.contextMenuHandler);            
+        },
+        value: true
+    }
+});
+
+});
+
diff --git a/lib/ace/keyboard/textinput.js b/lib/ace/keyboard/textinput.js
index 397a0917..049ddca4 100644
--- a/lib/ace/keyboard/textinput.js
+++ b/lib/ace/keyboard/textinput.js
@@ -96,8 +96,13 @@ var TextInput = function(parentNode, host) {
     function resetSelection(isEmpty) {
         if (inCompostion)
             return;
-        var selectionStart = isEmpty ? 2 : 1;
-        var selectionEnd = 2;
+        if (inputHandler) {
+            selectionStart = 0;
+            selectionEnd = isEmpty ? 0 : text.value.length - 1;
+        } else {
+            var selectionStart = isEmpty ? 2 : 1;
+            var selectionEnd = 2;
+        }
         // on firefox this throws if textarea is hidden
         try {
             text.setSelectionRange(selectionStart, selectionEnd);
@@ -180,26 +185,33 @@ var TextInput = function(parentNode, host) {
     var onSelect = function(e) {
         if (cut) {
             cut = false;
-            return;
-        }
-        if (copied) {
+        } else if (copied) {
             copied = false;
-            return;
-        }
-        if (isAllSelected(text)) {
+        } else if (isAllSelected(text)) {
             host.selectAll();
             resetSelection();
+        } else if (inputHandler) {
+            resetSelection(host.selection.isEmpty());
         }
     };
 
+    var inputHandler = null;
+    this.setInputHandler = function(cb) {inputHandler = cb};
+    this.getInputHandler = function() {return inputHandler};
+    
     var sendText = function(data) {
+        if (inputHandler) {
+            data = inputHandler(data);
+            inputHandler = null;
+        }
         if (pasted) {
             resetSelection();
             if (data)
                 host.onPaste(data);
             pasted = false;
         } else if (data == PLACEHOLDER[0]) {
-            host.execCommand("del", {source: "ace"});
+            if (Date.now() - lastCompositionTime > 100)
+                host.execCommand("del", {source: "ace"});
         } else {
             if (data.substring(0, 2) == PLACEHOLDER)
                 data = data.substr(2);
@@ -219,9 +231,8 @@ var TextInput = function(parentNode, host) {
         if (inCompostion)
             return;
         var data = text.value;
-        resetValue();
-
         sendText(data);
+        resetValue();
     };
 
     var onCut = function(e) {
@@ -344,10 +355,12 @@ var TextInput = function(parentNode, host) {
         if (!inCompostion) return;
         host.onCompositionUpdate(text.value);
     };
-
+    
+    var lastCompositionTime = -1;
     var onCompositionEnd = function(e) {
         inCompostion = false;
         host.onCompositionEnd();
+        lastCompositionTime = Date.now();
     };
 
     var syncComposition = lang.delayedCall(onCompositionUpdate, 50);
@@ -377,10 +390,11 @@ var TextInput = function(parentNode, host) {
         var style = dom.computedStyle(host.container);
         var top = rect.top + (parseInt(style.borderTopWidth) || 0);
         var left = rect.left + (parseInt(rect.borderLeftWidth) || 0);
+        var maxTop = rect.bottom - top - text.clientHeight;
         var move = function(e) {
             text.style.left = e.clientX - left - 2 + "px";
-            text.style.top = e.clientY - top - 2 + "px";
-        };
+            text.style.top = Math.min(e.clientY - top - 2, maxTop) + "px";
+        }; 
         move(e);
 
         if (e.type != "mousedown")
diff --git a/lib/ace/virtual_renderer.js b/lib/ace/virtual_renderer.js
index 719df69a..0de955cb 100644
--- a/lib/ace/virtual_renderer.js
+++ b/lib/ace/virtual_renderer.js
@@ -549,8 +549,8 @@ var VirtualRenderer = function(container, theme) {
 
         this.textarea.style.height = this.lineHeight + "px";
         this.textarea.style.width = w + "px";
-        this.textarea.style.right = this.$size.scrollerWidth - posLeft - w + "px";
-        this.textarea.style.bottom = this.$size.height - posTop - this.lineHeight + "px";
+        this.textarea.style.right = Math.max(0, this.$size.scrollerWidth - posLeft - w) + "px";
+        this.textarea.style.bottom = Math.max(0, this.$size.height - posTop - this.lineHeight) + "px";
     };
 
     /**