diff --git a/lib/ace/lib/lang.js b/lib/ace/lib/lang.js
index 863bbb55..13b76f77 100644
--- a/lib/ace/lib/lang.js
+++ b/lib/ace/lib/lang.js
@@ -89,13 +89,24 @@ exports.deepCopy = function (obj) {
         return obj;
     
     var copy = cons();
-    for (var key in obj) {
-        if (typeof obj[key] === "object") {
-            copy[key] = exports.deepCopy(obj[key]);
-        } else {
-            copy[key] = obj[key];
+    if (Array.isArray(obj)) {
+        for (var key = 0; key < obj.length; key++) {
+            if (typeof obj[key] === "object") {
+                copy[key] = exports.deepCopy(obj[key]);
+            } else {
+                copy[key] = obj[key];
+            }
+        }
+    } else {
+        for (var key in obj) {
+            if (typeof obj[key] === "object") {
+                copy[key] = exports.deepCopy(obj[key]);
+            } else {
+                copy[key] = obj[key];
+            }
         }
     }
+
     return copy;
 };