Im having the same issue the colour options are not even there. I can colour any other shed i have with no issues at all
do you have both the most up to date mods, I have no issues coloring my shop, I even tried it last night incase the update broke it and it’s just fine, so something is going on with your mods. Make sure both mods are up to the current version and make sure you don’t have an old design kit in your mods folder as that will conflict with the newer versions.