Remove line under Windows 10 taskbar icons

Question

That "underline" underneath taskbar icons was apparently added to indicate the application is open (vs. just pinned). I don't need this indicator.

Is there any way to remove the open application indicator that appears as a line underneath Windows 10 taskbar items?

I tried this custom theme, but it did not work. Other places where this has been asked:

• 7+ Taskbar Tweaker comments
• How do I remove the underline under programs with only 1 window open?
• Getting rid of the underline on active apps?

Solution

update: This solution had some weird side-effects, so I stopped using it. Leaving for historical purposes (and people who don't want to shell out a few bucks for the new solution I use.)

I figured it out: NoLine custom theme + UltraUXThemePatcher!

Upvote/comment if you'd like the files required with detailed instructions. (You can mess up your computer if you don't install the correct theme that matches your version of Windows.)