UI : navbar tooltip position fix when "loading" appears.

When the loading list item appears, the tooltip change its position:

##### Before clicking :
![before-click](https://f.cloud.github.com/assets/801718/758342/1781d91e-e72b-11e2-8d60-b08da78e40e0.png)

##### After clicking :
![after-click](https://f.cloud.github.com/assets/801718/758343/1fea6530-e72b-11e2-8b3e-e0b156277ec2.png)

This pull request fixes the issue.