Thanks for your reply.
> Also, don't forget you can copy/paste the theme you want (e.g. SnowFlat) and make any changes you want to that "new theme" you create.
That would be exactly the complete opposite of what I am looking for. If I copy paste, the moment the theme gets a new version I will have to redo the modifications.
I will check the layers, I think it will do the job. Thanks