I believe that it does have a purpose, it let's you know when you're changing syntax/languages. Perhaps making it a little bit darker than the actual background might be a better solution. It's nice in something that uses a template engine similar to HAML or ERB.

![lpo346](https://cloud.githubusercontent.com/assets/1622680/2542127/d5b06d6a-b5e3-11e3-892c-9b71ad709da1.png)