Simplesearch not working in Anitmatter theme

The default configuration has Category filter default to Blog. I want Simplesearch to search my entire site, so, I cleared the Category filter field, in the Admin interface, so Simplesearch would search my entire site and not be limited to searching just Blog.

What I have found is, when clearing the Category filter field in the Admin interface, it deletes the entire Category filter keys and value (Blog) in the config file rather than just deleting the value (Blog). This renders Simplesearch inoperable.

To fix this I put the Category filter keys back into the config file, manually, and left the value blank. Simplesearch then works perfectly.