Tab counter is broken in latest update

[HighCommander4]

Steps to reproduce

1. Update to today's TST version (4.0.14)
2. Use the steps at https://github.com/piroor/treestyletab/wiki/Code-snippets-for-custom-style-rules#tab-numbering-and-counting to show a tab count, for example:

#tabbar {
  counter-reset: vtabs atabs tabs;
  /* vtabs tracks visible tabs, atabs tracks active tabs, tabs tracks all tabs */
}
tab-item:not(.collapsed):not(.discarded) {
  counter-increment: vtabs atabs tabs;
}
tab-item:not(.collapsed) {
  counter-increment: vtabs tabs;
}
tab-item:not(.discarded) {
  counter-increment: atabs tabs;
}
tab-item {
  counter-increment: tabs;
}

:root.simulate-svg-context-fill .newtab-button::after {
  content: var(--tab-count-text);
  pointer-events: none;

  width: 100%;
  /* TST 2.4.0 - Fix for Issue #1664 */
  background: transparent !important;
  mask: none !important;
}

.newtab-button {
  --tab-count-text: counter(tabs) " tabs";
}

Expected result

Total tab count is shown in the new tab button.

Actual result

A smaller number is shown, and it changes as you scroll.

Environment

• Platform (OS): Linux
• Version of Firefox: 115.10.0esr
• Version (or revision) of Tree Style Tab: 4.0.14

---

I assume the CSS needs to be updated to reflect a change in the add-on, but I'm not sure what the update should be.

[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.

[github-actions[bot]]

This issue has been closed due to no response within 7 days after labeled as "wontfix", 7 days after last reopened, and 7 days after last commented.

[rixx]

FWIW, I built an addon that adds a tab count to the "new tab" button, if that helps.