For users with admin and super user access:
By default we would want all menus to be collapsed except for the menu that has an active item. Meaning if you are on the "General Settings" page then "System" section should be expanded, all other menus should be collapsed/closed.
On toggle you can open/close a menu.
If a user has view or write access, then the menu behaves as currently where all submenus are expanded (visible) by default as there are only few menu items available anyway.