MailHeaderBackground in Theme-File

I just tried to change the MailHeaderBackground color with a theme-file.
But the color won’T change. I just can change the color of the MessagePanelBackground
but then it’s the Header and Panel background and I want the panel white and the header
in a different color, so I have the header in light gray and  beneath the header white.
Hope this BUG will be fix soon. 

MessagePanelBackground will change both, but that is not what you want.

Richard usually provides very helpful comments on theme editing, but I haven’t seen anything from him in a while. :frowning: