Seems a user has reported a bug to me in the plugin. It only works when the collapsible panel is open. So if you start the app and the plugin panel is closed the app doesn't render with your selected background color.
I fixed this and he is testing the changes. Once he says it's OK and there are no other bugs found I will release the updated plugin. Hopefully that will be the final release necessary.
Thanks for all your help and for using my plugins.
Talk about anything else here.