my theme IS a mod of a V4 theme [CIRCUS is my version]
and it works just fine for both track and item custom colors
It can take a little work to set it up to make all that very easy
One step is to have the SWS extensions loaded and then create a set of custom colors for the SWS colors... [TIP: you can create and save as diff names several of those if you like and easily load each one as desired]
and\or just use the color wheel to pick your colors...
you can then create a floating toolbar that is dedicated to setting colors...
Mine has track colors on the left side, using each of my 16 SWS colors plus black and white ..and.. also the main color wheel...
on the right side of that tool bar is the same thing but only for items
then also there are some script actions that let you copy the color of any item and past it to any other selected items...
here is what mine looks like:
https://i.imgur.com/MdMZxX1.jpg