diff --git a/src/core/core.js b/src/core/core.js
index 6260c3a69..b2dcc0045 100755
--- a/src/core/core.js
+++ b/src/core/core.js
@@ -108,7 +108,11 @@
             var objClone = {};
             each(obj, function(value, key) {
                 if (obj.hasOwnProperty(key)) {
-                    objClone[key] = value;
+                    if (typeof value === 'object' && value !== null) {
+                        objClone[key] = clone(value);
+                    } else {
+                        objClone[key] = value;
+                    }
                 }
             });
             return objClone;