1) I've specified a DefaultBackgroundColor string in the info.plist (E6E6E6), but it doesn't seem to have any effect..it's stuck on white unless I enable a custom color.
2) Maybe this has to do with variants, but where do you set the faded-gray colors used for previous messages in a new message window?
1) Try setting it in the CSS too.
2) Context.html is the Content.html for Message History. Edit Context.html and the CSS file to get your desired effect.