I'm not sure if this applies to any other items that apply styles, but I was able to do it with the user title color one so far. With the vB version, all you had to do is make the item active in your inventory and it would apply the color to your user title. Now (on XF) it seems that you have to make it both active and unhidden to apply it. However, you can then hide it after you save it like this once and the color stays. So it's the same thing in the end, but it requires an extra step to force it through.