Improve ux when editing advanced config default

### old workflow
![old_workflow](https://cloud.githubusercontent.com/assets/1329312/4595997/97f28ffc-509e-11e4-85a3-efd6d0e1cada.gif)

### new workflow
![new_workflow](https://cloud.githubusercontent.com/assets/1329312/4595996/96c19376-509e-11e4-9666-69de5e77c761.gif)