Please see
this post
Please note, since this is commonly misunderstood, that the tintcp command has no effect whatsoever over colouring, it merely greys out in the preferences to indicate that the commands won't do anything
with the theme you are currently using. It indicates this very poorly, and has been a source of confusion since pretty much the day it was introduced
Changing it would allow you to change your global preference, which likely was already ticked anyway, but your theme would look the same.
If you want to change the custom colouring of a 'version 5' theme, you can either convert it to a pre-'version 5' theme and then use the old, very crude, colouring method (almost certainly not what you want), or you can swap out some backgrounds, for which I suggest asking the themer who made your theme.