Problem when compiling xfce4-notes-plugin

[Cristian Marchi]

I get an error when I try to compile xfce4-notes-plugin from git in a 
system with all the Xfce's component compiled from git.

make[2]: ingresso nella directory 
«/home/cristian/Xfce/xfce4-notes-plugin/lib»
   VALAC  libnotes_la_vala.stamp
icon-button.vala:117.3-117.33: error: Private member 
`Xnp.TitleBarButton.draw_icon' cannot be marked as override, virtual, or 
abstract
         private override void draw_icon (Cairo.Context cr, int width, 
int height) {
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Compilation failed: 1 error(s), 0 warning(s)
make[2]: *** [libnotes_la_vala.stamp] Errore 1
make[2]: uscita dalla directory «/home/cristian/Xfce/xfce4-notes-plugin/lib»
make[1]: *** [all-recursive] Errore 1
make[1]: uscita dalla directory «/home/cristian/Xfce/xfce4-notes-plugin»
make: *** [all] Errore 2


"autogen.sh" runs fine but when I run "make" I get this error. I've 
installed vala from git.

Thanks for any help
Cristian