How to enable selected tab highlight in vertical tabs mode.

[FosRexx]

I use vertical tabs mode with this Black by XI theme. And its very hard to differentiate between selected and non selected tabs when Lepton is installed. Here is the pictures for comparison.

With:

Without:

So how do i re-enable selected tab highlights in vertical tabs mode, with Lepton installed?

Everything is default. I also tried looking into user.js but could not find the setting I am looking for.