Fix the limitation of site registration.

#3271
![selection_013](https://f.cloud.github.com/assets/1222368/812419/81bfe750-eeef-11e2-9dcf-5c2706ad4816.png)
![selection_014](https://f.cloud.github.com/assets/1222368/812420/81e1dcb6-eeef-11e2-90fc-19bb653e088d.png)