Tab counter is broken in latest update

[HighCommander4]

Tab counter is broken in latest update

[piroor]

This is a known restriction of TST 4.0 and later.
https://github.com/piroor/treestyletab/blob/trunk/history.en.md

• 4.0 (2024.3.7)
  • Improved performance on cases with large number of tabs. Now tabs only in the viewport are rendered.
    (snip)
    • Due to this design change, customization with CSS counter won't be work as expected anymore. You'll need to create something helper addon to do such customizations.

[piroor]

As described at the changelog, CSS's counter customization no longer available, so you need to develop something helper addon to provide effective counter.