setSection
Sets or unsets the "section" link of @menu_item to @section.
The effect of having one menu appear as a section of another is exactly as it sounds: the items from @section become a direct part of the menu that @menu_item is added to. See g_menu_item_new_section() for more information about what it means for a menu item to be a section.
Since
2.32
Parameters
section
a #GMenuModel, or null