With the extension "Highlight category" you can, as the name says, highlight a category in the top navigation.
To do this, you activate the highlighting via a custom field in the corresponding category.
Highlighted category in top navigation
Note: A category is only highlighted in the top navigation if the "Highlight category" custom field is set to "yes" for it. The theme configuration only controls the appearance of the highlighting.
Guide: You can find a step-by-step guide in the ThemeWare® Wiki:
Configuration
Theme configuration
Go to the "Header" tab
Expand the "Top navigation" block
Scroll to the section "Link (highlighted)"
Now configure the highlighting as you like
Save your changes after editing
Switch via the main navigation to the "Category managment" (1) (2) ("Catalogues" => "Categories")
Choose the category you want to edit (3)
To the right of the category list, the corresponding category now opens in the category editor (4)