Think you might need to include a screenshot of what you’re trying to do because I’m not getting an image of what you’re trying to accomplish.
Thank you for your reply,
If your question is about "coloring" the icons / file names / title previews in a book file: That's not possible. However, you can combine one or multiple files in groups or folders in the book file. Check the FrameMaker 2015 Online Help – Set up hierarchical books for more details.
Thank you very much Stefan. Have a nice weekend, regards, Esther
You're welcome, Esther. Please feel invited to mark my answer as "Correct Answer", so that we can mark this question as "Answered" and can close it 🙂