Trying to get Reactions to work

I’m really trying to understand Reactions by myself, but it seems it’s really hard to do anything without good knowledge of both the LOM and Python…

Anyway, here’s what I’m trying to achieve :
– when Live’s playback is running, send 127 on CC10
– when Live is stopped, send 0 on CC10

pretty simple, right ?

I have done the attached Reaction, but nothing happens (Button1 is set to CC10).

If anyone can help me, I’d be grateful. Thanks