MIDI channel Key slider not working

Hi guys, 
 
I may be missing something but I do not seem to be able to make the "Key" slider in a MIDI channel to work.  The track is played back in the same key no mater what value the Key slider is in.  I have other MIDI track in the same project and it does not have that problem (i.e the Key slider does change the key at which the notes are played back). Any ideas how to solve this?
 
Thank you.
 
Jhon