FOR VERSION 3.0.9 OR EARLIER ONLY
In this short guide we will show you how to set an specific menu point (for example 'Work' or 'Portfolio') as active while you are looking at a project.
1. Go to 'Appearance' -> 'Menus'
2. On the top right click on 'Screen Options' and select 'CSS Classes' if it's not already selected.
3. Now select the page that contains your portfolio grid and click on the small arrow on the right side of the menu item to slide down the options.
4. Now in the options please enter 'portfolio-grid' (without the quotes) into the field 'CSS Classes'.
5. Done! The page with the portfolio grid now acts as your parent menu item for the portfolio and gets highlighted if you view a project.