The menu example in the examples/menu directory of the GTK+ distribution implements a popup menu with this technique:
static gint button_press (GtkWidget *widget, GdkEvent *event) { if (event->type == GDK_BUTTON_PRESS) { GdkEventButton *bevent = (GdkEventButton *) event; gtk_menu_popup (GTK_MENU(widget), NULL, NULL, NULL, NULL, bevent->button, bevent->time); /* Tell calling code that we have handled this event; the buck * stops here. */ return TRUE; } /* Tell calling code that we have not handled this event; pass it on. */ return FALSE; }