I did this once, but somehow I could not figure out how to replicate it upon the recent reinstallation of Nexus Ultimate. The indicators were using arrows from K-TEK 4D and then somehow changed to the current ones, which look similar to the files in DarkTech and Office. Since then, the indicators don't change at all when I swap between different themes.

What I have done so far:
- Moved the arrow icons from Themes/DarkTech, Themes/K-TEK 4D, and Themes/Office to somewhere else. Which in my mind should prevent Nexus from reading those files.
- Set the shelf theme to DarkTech.

Those are the *default* sub-dock indicator arrows - that's what the application will use if the theme used by that dock does not provide its own sub-dock indicator bitmaps (nxSubC.ico/.png/.tif)

You have the background of that dock set to fully transparent, so it's not possible to know which theme the dock is using - but whatever it is, it does not have a nxSubC.ico/.png/.tif file.

It is running DarkTech with all arrow icons removed, so it makes sense that the program is running the default arrows. Is there a way to turn off the default arrows? Alternatively, I could create a transparent nxSubC icon file if that works.

This ^

Happy to report that the idea worked like a charm. Topic resolved.