Fixed commit stats barchart popup jumping.

The bug's capture:

![gitlabbug](https://f.cloud.github.com/assets/1243254/1054963/858fdbd0-1120-11e3-8610-24f3d3ecb2f2.gif)

And now fixed:

![gitlabfixed](https://f.cloud.github.com/assets/1243254/1054966/a40d7ed2-1120-11e3-8070-bdd217c81a2c.gif)