Im actually having the same issue, however ive not activated the right side though, mine is just the background issue
Ive just wrote an article and assigned it a new background of its own, however it wont show it and reverts to the default one set in the theme options page.
Article is here >> http://www.jamespictures.co.uk/beginners-guide-to-social-media-for-photography/
2 background images assigned >> http://jamespictures.co.uk/images/background_problem.jpg
im still using v1.7 of the theme as ive only just noticed there is an update, If I get time tomorrow I will update the theme, but I dont think this is the issue as its working on other pages just fine.
Background changes fine using the same method as above
Its also extremely bizarre how this blog post changes the background just fine
I dont get it ;-)
I will do some more playing to see why its not changing the BG image