Enabling PreProcess extension inappropreatel also enables WellForm check

With preprocess enabled off

![wo-preproc](https://f.cloud.github.com/assets/348314/144072/526daa70-73eb-11e2-8afd-6dd8a72ece5b.png)

with preprocess on

![preproc](https://f.cloud.github.com/assets/348314/144070/3d4a04c2-73eb-11e2-8426-7f38adf5a9ab.png)

Well form check should not be added unless necessary.

This is a big deal because we are planning on enabling preporc by default, so don't want to add WellForm check unnecessarily.