fcarosone
I had enabled W in the channel strip, they are not linked.
I believe regular FX ARE linked by default. By this I mean that if you add a VST to an Audio track and write enable the audio track it will write enable the VST as well.
Midi/Soft-Synths are different. If you Write Enable a Midi track it DOES NOT Write Enable the Soft-Synth that the Midi Track outputs to. This behavior is the same for Simple Instrument Tracks. You have to explicitly Enable Write on the Soft-Synth.
I believe that the goofy behavior I describe with TH2 may be related to the fact that you CAN specify TH2 to work as a Soft-Synth and set the midi output from a midi track to be input into TH2 so that you can automate TH2 that way. The problem is that the W for write enable gets changed to red on the TH2 in some cases where write is NOT actually enabled. That's really the bug.
So Sonar marks the W Red because it's a VST plug, but then doesn't actually write enable TH2. This makes TH2 a special case, a bit like dropping a Soft-Synth into the FX bin of an audio track and using the Synth as an effect on the track. So, perhaps if you drop Pentagon onto an Audio Track to use it as a Vocoder, you would get the same behavior.
Also, it may have to be on a cold start. And I was using the full version of TH2, not the Sonar Version.
This is not the same for other FX. For example, if you add a regular VST to an audio track and write enable the audio track, it will create the related envelope when you twiddle a pot.