Option Default

I’ve just started using Sunrise (so far it’s been pretty nice), I am creating an options page, to which I have added some radio buttons. When I view the admin page, the ‘std’ button is not selected by default. It does however get selected if I click ‘Restore default settings’. I notice this did not happen with the sample radio buttons included..

https://www.ads-software.com/extend/plugins/sunrise/