Expression Pedal controlling selected track volume

[John Allsup]

I've just connected an expression pedal to my Yamaha CP50. Moving it causes the volume of the selected track to be changed, and not sent as a CC to the track itself (i.e. midi monitor shows nothing). How do I change this so that Reaper doesn't intercept the expression pedal messages? (And how to configure things so that the pedal controls other things?)

Disabling 'control messages' in the MIDI device prefs stops this. But I'm wondering how to configure behaviour such as this.