i’ve been using wordpress beta versions. after a recent update to 4.9 beta (sorry i didn’t record the full version number) – i’ve discovered that i can’t edit the generate press header content section. this problem disappeared after i reverted back to the 4.8.1 stable version. thought you should know.
It looks like the nightly version introduced a bug when dealing with color pickers. 4.9 is in alpha, so things like this can happen. It will likely be fixed. We’ll keep an eye on it 🙂