Pull Request resolves #45490 .

• 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

Fixes the display of an administrator menu separator when it is the first item in the menu.

The separator filtering logic in CssMenu.php initialised $noSeparator to true, which caused the first separator encountered to be treated as a repeated separator and removed.

The initial value is changed to false, allowing the first separator to be displayed while retaining the existing behaviour of removing consecutive separators.

Testing Instructions

Create an admin menu, an admin menu Modul an place it on position Administrator Menu
Create several admin menu items: a, b, c, d, e, f.
Create separators: s1, s2, s3.
Arrange the items and separators in the following order: s1, a, b, s2, c, d, s3, e, f.

Actual result BEFORE applying this Pull Request

The first separator (s1) is not displayed. The menu appears as: a, b, s2, c, d, s3, e, f.

Expected result AFTER applying this Pull Request

The menu items are displayed in the following order: s1, a, b, s2, c, d, s3, e, f.

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