GtkMenuShell::select_item

select_item() is largely used internally. A 'selected' item is displayed in the prelight state and has its submenu popped up, if it has one. This is also achieved by using the mouse pointer or arrow keys in an active GtkMenu, and should not be confused with the "activate" signal, which is triggered by mouse clicks or the Enter key.

Using this method causes the designated item to emit the "select" signal, which in turn triggers the 'selected' state.