fix close button of top page message overlap text

before
![png-1](https://cloud.githubusercontent.com/assets/1492162/3190250/770ee550-eccc-11e3-96fe-dd726f13748d.png)
after
![png](https://cloud.githubusercontent.com/assets/1492162/3190253/7c2b23aa-eccc-11e3-9e7d-c35436a84be0.png)

@kaelig @tudorraul Have you tested the effect of this on other live messages such as the smart app banners? If not please do.