Menu Sync opens menus based on the path being presented.
All configuration is done at admin/content/menusync.
Menu Sync uses paths to define the pages affected.
The method used by Menu Sync to set the desired menu option allows it to affect more than one menu in the same page.
It cannot affect neither the primary links nor the secondary links menus as these two menus don't use the core Menu module. But remember that you don't have to use these menus at all.
Comparison with Menu Trails
Menu Sync is similar to Menu Trails but it uses paths to define the pages affected.
Another important difference between Menu Sync and Menu Trails is the method used to set the desired menu option. The method used by Menu Sync allows it to affect more than one menu in the same page. Apparently this is not possible with Menu Trails.
Neither Menu Sync nor Menu Trails can affect the primary links and the secondary links menus.
Menu Sync documentation is available through Advanced Help pages. Please install and enable Advanced Help module to access the documentation.
Please report any problems at the projects issue queue.