This setting does not appear to work with the 'use modern style' feature selected.
All of the tabs appear the same color and it is extremely difficult to determine which tab is active.
Here is what it appears as when the modern style is disabled:
Hi,
You're right. This is tricky since we use a predefined style. When you disable the modern style the highlight is available by default.
It's really hard to change a style but I will try to make tweak for the next version
David Hervieux