Property "notes" for clip is not working ?

[chapelier fou]

According to the LOM, an observer binding to a clip should be able to listen to the "notes" property and then output a bang when the notes change.
It doesn't seem to work.

EDIT : I seems to work just fine now. I must have been doing something stupid, don't know what.

EDIT : found what was my problem. I was observing the currently PLAYING clip but was doing my tests without the transport running.