Pull Request resolves Issue found CMS release team testing session on: February 12, 2026 (alternative to #47268).

• I read the Generative AI policy and my contribution is either not created with the help of AI or is compatible with the policy and GNU/GPL 2 or later.

Summary of Changes

Server-side active path detection to prevent flashing icons in admin menu sidebar with fallbacks for edge cases.

Menu active state detection and propagation:

• Added a new setActivePath method to mark the active menu path server-side. The existing JS logic was largely transferred 1:1 to the backend method.

JavaScript integration and fallback logic:

• Modified admin-menu.es6.js to strip server-rendered mm-show/mm-active classes before initializing MetisMenu, then re-apply them to avoid transition issues and ensure the active state is preserved without visual glitches.
• Added a client-side fallback in admin-menu.es6.js to detect and set the active menu item if the server-side logic fails.

Testing Instructions

Open the Joomla backend, expand the Components menu, and select one of the submenu entries.

Test other submenu entries to see if the icons are glitching and if everything loads directly without flickering with the fix.

You need the Firefox browser to test this, as the flickering is no longer noticeable on Chromium-based browsers (see #45787)

Additional test that deep nesting also works as expected - see #46550

Actual result BEFORE applying this Pull Request

Glitching icons in the admin menu sidebar when opening a submenu item as the active page

Expected result AFTER applying this Pull Request

Link to documentations

Please select:

• Documentation link for guide.joomla.org:

• No documentation changes for guide.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed