ProChannel Leveler Comp works only on certain tracks

I am consistently running into a problem in both Sonar x1 and x2:
 
The ProChannel Level Comp plug-in only seems to work on some - but not all tracks. I can tell because the gain reduction meter is moving in some displays - but not in others.
 
Levels have been adjusted - so it is not a matter of track level and comp settings.
 
Any ideas would be appreciated.