Hello,
You can change that color to some other color, but, no, you can not disable it altogether. If you wish, you can use Windowblinds which use the skin/theme taskbar button design.

Thanks
Basj,
Stardock Community Assistant.

I too find the small grey underlines that appear below each app in the taskbar distracting, but haven't been able to find a solution for removing them. The one that someone posted that they say has worked for them here:
https://www.thewindowsclub.com/rebuild-icon-clear-thumbnail-cache-windows-10
is over my head and I wouldn't want to mess with it.

Any chance an option can be added to remove these small grey underlines? I don't mind the longer blue underline that appears on the app that's in focus but don't really mind if that one is removed either.

Thank you.

That's much better. Thank you for your help!

Would be fantastic if the Windows 10 style long underline only appeared on the app in focus. In my opinion that would make things clear and clean looking without being distracting.

Understood, though in my opinion the underline on all of them isn't necessary because if it's pinned but not running then it'll appear as just an icon with no text and much smaller width, so it would be obvious that it's not running.

To me the most important thing to know is which app is in focus, but ideally in a clean, obvious but undistracting way. I think having the Windows 10 style underline appearing *only* on the app in focus would make it perfect. My two cents.