[@jaredatch Member 14 years, 5 months ago]

You will need to do some custom development on your end. This isn’t implemented in core (at least not yet) because at the moment each theme/framework handles their layout options differently – so there is no easy way to cover them all.

You can probably use the code in https://wordpress.org/extend/plugins/bbpress-genesis-extend/ as an example.

Basically you will want to check for is_bbpress() and if that comes back true then run your code that forces the full width layout.