[Scribus] PDF/X-3 tab disabled?

[Riku Leino Tsoots]

Laurent Cocea wrote:
>  I wonder if there is some other feature I need to
> enable first for this to work, or is this "by design" in the
> RedHat/Fedora build I got.

You'll probably need first disable pdf transparency option in 
preferences -> general. You'll also need to make icc color profiles 
available to Scribus and then turn the color management on in 
preferences -> color management.