This is an active trail issue.
For "most" situations, what you need to do is to assign the sub items to the same branch as the about. This "should" work.
If it is not, then it could be an issue with the theme and how the theme sets the active element in the menu.
In the more complex projects, setting active trail can become complicated with Drupal; and in those instances I actually write the menu in PHP in the template.php file and then print it on the page.tpl.php using a funciton-return.
Using this method is my "last resort" but it does allow me to make all nodes of a particular type mixed with node's of a particular number and arguments of a particular value all drive the same active trail logic in the menu's "class="active" system.
So,to sum: Ideal situation: use the drupal-way if you can [setting menu items as hierachichal]; but if you can't because you are mixing types with arguments with nid's; then use a function for the menu in template.php
Fred Jones wrote:
I have a site with a primary nav across the top and secondary on the left sidebar. When you browse to the About Us page via the top nav, then of course that item is highlighted with CSS class "active."
But if you then browse to one of the items in the subnav there, like Our History, the About Us on top is no longer active. Now this left hand secondary nav bar is actually a block made by the Tree Menus module.
Now they want of course the About Us to be active for all the subnav items, and the same idea for all the different pages, meaning the subnav items of "Our Programs" should all load with "Our Programs" active in the top nav. In the primary nav, Our History has About Us as its parent--of course they're all like that.
So really the question is I think: How can I tell the primary nav to make "active" the parent of the menu item from the Tree Menu block on the left?
Thanks