Scope dropdown multi-column CSS to navigation menus

[jjroelofs]

Linked issues

• Dropdown multi-column CSS leaks into non-navigation dropdowns #791

Solution

The multi-column dropdown layout rule in scss/vendor-extensions/bootstrap-5.scss used .dropdown-menu:not(.dropdown-full-width .dropdown-menu) nested under .html, making it effectively global. This applied float: left, display: block, and min-width to <li> elements inside every Bootstrap .dropdown-menu on the page — including dropdowns from third-party modules and non-navigation components.

Fixed by scoping the selector to .nav .dropdown-menu:not(...), restricting it to Bootstrap navigation contexts. This is consistent with:

• enhanced-dropdowns.js initAutoColumns() which targets .navbar-nav > .nav-item.dropdown > .dropdown-menu
• dxpr-theme-header--top.scss which scopes its dropdown rules under .block-system-menu-blockmain

Checklist

• I have read the CONTRIBUTING.md document.
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• My code follows the coding standards and style of this project.
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Need to run update.php after code changes
• Requires a change to end-user documentation.
• Requires a change to developer documentation.
• Requires a change to QA tests.
• Requires a new QA test.
• I have updated the documentation accordingly.
• All new and existing tests passed.