The Palette is popped down when an item is activated. We can
listen on the 'button-release-event' on that widget. We make
sure the widget is of type PaletteMenuItem. This is similar
to what the GtkMenu is doing, see gtk_menu_shell_button_release [1].
[1] http://git.gnome.org/browse/gtk+/tree/gtk/gtkmenushell.c#n915
Signed-off-by: Simon Schampijer <simon@laptop.org>
Acked-by: Manuel Quiñones <manuq@laptop.org>
