diff --git a/lib/ace/edit_session.js b/lib/ace/edit_session.js
index 9c57038c..ab385cfa 100644
--- a/lib/ace/edit_session.js
+++ b/lib/ace/edit_session.js
@@ -515,8 +515,7 @@ var EditSession = function(text, mode) {
         this.tokenRe = mode.tokenRe;
         this.nonTokenRe = mode.nonTokenRe;
 
-        if (mode.foldingRules)
-            this.$setFolding(mode.foldingRules);
+        this.$setFolding(mode.foldingRules);
 
         this._dispatchEvent("changeMode");
     };
@@ -641,7 +640,7 @@ var EditSession = function(text, mode) {
         this.$fromUndo = true;
         var lastUndoRange = null;
         for (var i = deltas.length - 1; i != -1; i--) {
-            delta = deltas[i];
+            var delta = deltas[i];
             if (delta.group == "doc") {
                 this.doc.revertDeltas(delta.deltas);
                 lastUndoRange =
@@ -666,7 +665,7 @@ var EditSession = function(text, mode) {
         this.$fromUndo = true;
         var lastUndoRange = null;
         for (var i = 0; i < deltas.length; i++) {
-            delta = deltas[i];
+            var delta = deltas[i];
             if (delta.group == "doc") {
                 this.doc.applyDeltas(delta.deltas);
                 lastUndoRange =
@@ -908,7 +907,7 @@ var EditSession = function(text, mode) {
             if (useWrapMode) {
                 var len = this.getLength();
                 this.$wrapData = [];
-                for (i = 0; i < len; i++) {
+                for (var i = 0; i < len; i++) {
                     this.$wrapData.push([]);
                 }
                 this.$updateWrapData(0, len - 1);
@@ -1070,7 +1069,6 @@ var EditSession = function(text, mode) {
         } else {
             // Realign folds. E.g. if you add some new chars before a fold, the
             // fold should "move" to the right.
-            var column;
             len = Math.abs(e.data.range.start.column - e.data.range.end.column);
             if (action.indexOf("remove") != -1) {
                 // Get all the folds in the change range and remove them.
@@ -1158,7 +1156,6 @@ var EditSession = function(text, mode) {
             return [];
         }
 
-        var tabSize = this.getTabSize();
         var splits = [];
         var displayLength = tokens.length;
         var lastSplit = 0, lastDocSplit = 0;
@@ -1414,7 +1411,6 @@ var EditSession = function(text, mode) {
         var docRow = 0;
         var docColumn = 0;
         var column;
-        var foldLineRowLength;
         var row = 0;
         var rowLength = 0;
 
@@ -1514,8 +1510,6 @@ var EditSession = function(text, mode) {
         docRow = pos.row;
         docColumn = pos.column;
 
-        var LL = this.$rowCache.length;
-
         var wrapData;
         // Special case in wrapMode if the doc is at the end of the document.
         if (this.$useWrapMode) {
@@ -1531,7 +1525,6 @@ var EditSession = function(text, mode) {
         }
 
         var screenRow = 0;
-        var screenColumn = 0;
         var foldStartRow = null;
         var fold = null;
 
diff --git a/lib/ace/editor.js b/lib/ace/editor.js
index 4953f3d3..67dda7bb 100644
--- a/lib/ace/editor.js
+++ b/lib/ace/editor.js
@@ -43,7 +43,6 @@ define(function(require, exports, module) {
 require("./lib/fixoldbrowsers");
 
 var oop = require("./lib/oop");
-var event = require("./lib/event");
 var lang = require("./lib/lang");
 var useragent = require("./lib/useragent");
 var TextInput = require("./keyboard/textinput").TextInput;
@@ -296,9 +295,10 @@ var Editor = function(renderer, session) {
     this.onDocumentChange = function(e) {
         var delta = e.data;
         var range = delta.range;
+        var lastRow;
 
         if (range.start.row == range.end.row && delta.action != "insertLines" && delta.action != "removeLines")
-            var lastRow = range.end.row;
+            lastRow = range.end.row;
         else
             lastRow = Infinity;
         this.renderer.updateLines(range.start.row, lastRow);
@@ -445,7 +445,7 @@ var Editor = function(renderer, session) {
 
         // remove selected text
         if (!this.selection.isEmpty()) {
-            var cursor = this.session.remove(this.getSelectionRange());
+            cursor = this.session.remove(this.getSelectionRange());
             this.clearSelection();
         }
         else if (this.session.getOverwrite()) {
@@ -548,7 +548,7 @@ var Editor = function(renderer, session) {
     };
 
     this.getScrollSpeed = function() {
-        return this.$mouseHandler.getScrollSpeed()
+        return this.$mouseHandler.getScrollSpeed();
     };
 
     this.$selectionStyle = "line";
@@ -804,7 +804,7 @@ var Editor = function(renderer, session) {
     this.removeLines = function() {
         var rows = this.$getSelectedRows();
         var range;
-        if (rows.first == 0 || rows.last+1 < this.session.getLength())
+        if (rows.first === 0 || rows.last+1 < this.session.getLength())
             range = new Range(rows.first, 0, rows.last+1, 0);
         else
             range = new Range(
@@ -862,7 +862,8 @@ var Editor = function(renderer, session) {
             range.start.row += linesMoved;
             range.end.row += linesMoved;
             selection.setSelectionRange(range, reverse);
-        } else {
+        } 
+        else {
             selection.setSelectionAnchor(rows.last+linesMoved+1, 0);
             selection.$moveSelection(function() {
                 selection.moveCursorTo(rows.first+linesMoved, 0);
@@ -1017,7 +1018,7 @@ var Editor = function(renderer, session) {
 
     this.gotoLine = function(lineNumber, column) {
         this.selection.clearSelection();
-        this.session.unfold({row: lineNumber - 1, column: column || 0})
+        this.session.unfold({row: lineNumber - 1, column: column || 0});
 
         this.$blockScrolling += 1;
         this.moveCursorTo(lineNumber-1, column || 0);
diff --git a/lib/ace/mode/folding/fold_mode.js b/lib/ace/mode/folding/fold_mode.js
index 1f941c00..c775d6cf 100644
--- a/lib/ace/mode/folding/fold_mode.js
+++ b/lib/ace/mode/folding/fold_mode.js
@@ -50,10 +50,16 @@ var FoldMode = exports.FoldMode = function() {};
 
     this.getFoldWidget = function(session, row) {
         if (this.foldingStartMarker) {
-            if (this.foldingStopMarker)
+            if (this.foldingStopMarker) {
+                // rewrite getFoldWidget so the check is only performed once
+                FoldMode.prototype.getFoldWidget = this.$testBoth;
                 return this.$testBoth(session, row);
-            else
+            }
+            else {
+                // rewrite getFoldWidget so the check is only performed once
+                FoldMode.prototype.getFoldWidget = this.$testStart;
                 return this.$testStart(session, row);
+            }
         }
         else
             return "";
@@ -65,7 +71,8 @@ var FoldMode = exports.FoldMode = function() {};
 
     this.indentationBlock = function(session, row) {
         var re = /^\s*/;
-        var startRow = row, endRow = row;
+        var startRow = row;
+        var endRow = row;
         var line = session.getLine(row);
         var startColumn = line.length - 1;
         var startLevel = line.match(re)[0].length;