fixed some issue when spinner is used with .add-on

From this ugly thing:
![spinner_before](https://f.cloud.github.com/assets/171747/1288574/f33c2784-300f-11e3-811d-b7f03cc813bb.GIF)

fixed some styles and created this:
![spinner-after](https://f.cloud.github.com/assets/171747/1288577/046075a6-3010-11e3-8e3d-c79d5daf4bde.GIF)