Mhmm, maybe I'm bad in explaining... I could blame my bad english skills... I try it once more: I don't said that we necessarily should support theming, but if we do it makes most sense to switch themes in a global manner. That does not imply to force the apps! At least it shouldn't imply that and I cannot believe it does. So lets say you can set a theme in the settings. Think of it as a suggestion. Then the app can, if that has been implemented, look at this setting and use the theme set globally. Nobody would be forced to anything, but nonetheless the user could set the theme globally for all those apps supporting it. Maybe there are better concepts than theming - it wasn't my intention to discuss that...