I’m trying to do this:

1. Disarm current track.
2. Move to next track.
3. Arm current track.

I’m ending up with the first track armed. Putting a breakpoint between 2 and 3 makes it work properly.

Update: it seems to be working fine when mouse clicking the buttons, but not with a midi note triggering it when mapped in ableton. I have another post about that: http://cycling74.com/forums/topic.php?id=23509