Fixed positioning won't uncheck, causing issues

@douginconcert – Sorry about that, this is a known bug, it has been patched in the latest beta and should be out soon. Or you can patch it manually https://gist.github.com/danieliser/c15fedc08848137796e9.

Currently whatever setting you saved last is what is used, but the checkbox always appears checked at first, meaning you have to uncheck it each time you save.

Hope that helps.