I have GP Premium 1.5.6 running on 2 different websites. On one I can customize the colors without any problems. On the other it’s not possible. Colors is activated in the Options.
Whenever I go to Colors > and then any of the choices (Body, Header, etc.) the choices are there (Background Color, Text Color, etc.) but they only exist as text. There’s nothing to click or any options at all to change any of the colors.
If I Deactivate Colors in the options I get the exact same results as I do when Activated.