cello

Surely a bug... I started to have the same problem after i switched to 10.0.7 from 10.0.4 (it behaved as expected before) and i just found another workaround: after creating the stack, open the smart control panel in the main bus, then manually assign the control to the desired track's parameter. Now it should fetch midi from the controller again. This technique can be handy to have controls over all your instruments inside a stack or map controls from different instruments to a single knob. smart controls are limited to plug-ins parameters, if you want to automate modulation you need to use midi draw. In case you want to use a midi controller for that, your unit needs to have a knob/fader assigned to cc#1. most of the modern controllers are provided with software to change the midi mapping of the unit.