Show a menu item as expanded if on a certain node type I have a News menu item, which then has children. I need it to be expanded if it is on a news article page, but not expanded on other certain pages.

I'm not sure which hook to use. i've played around with menu_link_alter but i can't figure out how to choose the item i'm on in order to process it. Maybe this isn't the correct way.

Any ideas please?
I would go with the context module.

You can set a context to be active whenever a certain content type is shown, in this case, an 'Article'.

You can then set the reaction to 'menu' and choose an item which will get an active trail. You can then target using CSS or more likely, it's probably already expanded.

https://drupal.org/project/context