Clip automation has no effect

The MIDI CC envelopes on clips don't have an effect on the actual MIDI data, but if I draw the events in the piano roll, those work.  So, with a clip, I select MIDI from the drop down box, assign it to a CC (7, 11, whatever) on the same channel and draw away.  There is no change in sound afterwards, so the envelope does not appear to be working.  When I go to Piano Roll for the same channel and edit the CC data in the lane, it works great.  I don't mind using PR, but the clip envelopes give me more options besides just a straight line up and down.  What am I missing?