Thank you for your post.
We have had previous reports of this issue. Testing and Development came back to say it is expected behavior. However, I recommend entering a suggestion into the Feature Requests Web Form for a possible change in functionality.
You can copy the style from one Button Bar and paste it to another Button Bar. You are unable to copy the style from the individual parts of a Button Bar (dividers, segment, and icon).
Additionally, I have added this post to our previous reports.