select() makes the calling GtkMenuItem emit the "select" signal inherited from GtkItem.

In the GtkMenuItem widget, the emission of the "select" signal causes the widget to display its prelight GtkStateType and pops up its submenu, if it has one.

Note that the "select" signal is also emitted whenever a GtkMenuItem is entered by the cursor, and by the first item in a GtkMenu when it is popped up.