To my surprise I found that there is still MIDI crosstalk in Sonar. I thought this was finally fixed in Kingston:
 

From improving selecting and bouncing, to eliminating MIDI crosstalk once and for all...
http://static.cakewalk.com/cakewalk/products/sonar/release_notes/SONAR_Kingston_Update.pdf

 
When I select as a MIDI track's input:
 
[My external MIDI keyboard]->OMNI
 
...then MIDI events coming from VSTis that have Enable MIDI Output are happily recorded with my external MIDI keyboard's events onto the track.
 
And just to be clear... In this context OMNI means all 16 channels from the external MIDI keyboard, not every single MIDI event floating around inside Sonar.

Why are you calling this crosstalk? If MIDI messages are being sent to Sonar by any means I would expect them to be captured by any track recording input MIDI omni=all channels. Why not just set your keyboard to broadcast on a single channel, set your recording track to that channel, and make sure other MIDI message sources are either disabled or broadcasting on another channel? I have no idea how you can set a track to just receive messages from a single controller vs a specific channel. If the controller is set as a MIDI input to Sonar (the program as a whole), does it not tell Sonar to accept messages to Sonar for any enabled track on the sending channel?

You're misunderstanding the OP I think. Selecting your keyboard OMNI as input is not the same thing as selecting global OMNI. I wouldn't expect any VSTi generated midi to be captured by a midi track if I specifically selected only "all channels from my external keyboard". 

Hi Silktone,
 
I'll check this out later, but suggest you double-check that what is shown in the Input field is the only thing checked in the pick list. I encountered a situation recently where more than one input port was checked when I opened the Input drop-down. I was not able to repro how the track got into that state, but as soon as I re-selected only the input I wanted, the problem was resolved and stayed that way.

I'm not seeing a problem. I set up:
 
Track 1 Plays an existing MIDI clip with dupe events on channels 1 and 2, and outputs to LoopBe Out.
Track 2 Records Hardware MIDI In - Omni
Track 3 Records LoopBe In, Ch1 , transposes it up two octaves with key+ and echos to Blue Arp
Track 4 Records Blue Arp MIDI Out Ch1
Track 5 Records LoopBe In, Ch2
 
I arm tracks 2-5 and record while playing live with the keyboard sending to the hardware MIDI IN on Ch 1. I stop recording and check all tracks. Each records only its assigned input port and channel.
 

I have noticed recently that my BFD tracks will trigger my other VSTs if I don't go to the other MIDI tracks and specifically select the MIDI input corresponding to my MIDI keyboard.
 
I suppose it's cleaner to actually set the MIDI input like this, but I never had to do it before.

A little OT but I still don't understand why "none" doesn't just mean "none." 
 
Sometimes you don't want ANY MIDI reaching a track and it's ridiculous that you should have to be selecting anything but "none" to do this. 
 
Every time I insert Jamstix into a project and use its MIDI-out I encounter the familiar annoyance of having Jamstix playing a freaking crazy-ass bass line on another track until I set that track's MIDI input to my keyboard. Sort this out Cakewalk!

slartabartfast
Why are you calling this crosstalk? If MIDI messages are being sent to Sonar by any means I would expect them to be captured by any track recording input MIDI omni=all channels. Why not just set your keyboard to broadcast on a single channel, set your recording track to that channel, and make sure other MIDI message sources are either disabled or broadcasting on another channel? I have no idea how you can set a track to just receive messages from a single controller vs a specific channel. If the controller is set as a MIDI input to Sonar (the program as a whole), does it not tell Sonar to accept messages to Sonar for any enabled track on the sending channel?

That is not how it is supposed to work. What you suggest is a workaround for a bug. And the input wasn't selected as OMNI, it was selected as [My external keyboard]->OMNI.
 
It is perfectly valid for a keyboard to have a split and send on multiple MIDI channels based on key zone. If that is what I want to record into one track then Sonar cannot do that. That is a pretty basic shortcoming for a DAW in 1995, let alone 2016.
 
BTW I'm not sure why that comment was marked as helpful seeing as it is completely wrong.

brundlefly
I'm not seeing a problem. I set up:

This issue is very specific to VSTis generating MIDI events internally as opposed to playing back prerecorded MIDI clips. For instance Catanya and JamStix will reproduce this.
 
I have also seen this issue not reproduce if there are multiple external MIDI inputs.
 
BTW I confirmed that the external MIDI keyboard is the only thing selected as input.

sharke
A little OT but I still don't understand why "none" doesn't just mean "none." 
 
Sometimes you don't want ANY MIDI reaching a track and it's ridiculous that you should have to be selecting anything but "none" to do this. 
 
Every time I insert Jamstix into a project and use its MIDI-out I encounter the familiar annoyance of having Jamstix playing a freaking crazy-ass bass line on another track until I set that track's MIDI input to my keyboard. Sort this out Cakewalk!

Good question. My impression of Sonar is that the whole concept of VSTis sending MIDI out was never tested and never considered in the overall design.
 
For instance, the default input for a MIDI track is "None", which is synonymous for "Global OMNI" (why?). That kinda works where you have a MIDI keyboard connected and you want the selected track to automatically receive input from the MIDI keyboard. Very convenient.
 
However CW seems to have forgotten that there are also VSTis that can send MIDI out as well, so now the default is for a selected track to receive MIDI from the external keyboard as well as any and all VSTi that happen to send MIDI out. In most cases I would guess that the MIDI out from a particular VSTi has already been purposefully routed into another track. So why on earth would anyone want every single MIDI event to now suddenly appear on the selected, yet unrelated track?
 
Well, fortunately one can specifically change the input of a MIDI track to a specific port. This way, the MIDI events of other VSTis should be ignored, even if OMNI was selected for that specific port (the output of a VSTi is a completely different port). However it still doesn't work in Sonar, and every single MIDI event floating around in Sonar that was sent out by a VSTi will also be recorded onto a track that has been routed to a port that has nothing to do with any of those VSTis.
 
This is MIDI 101. I still don't understand why this is so hard for CW to get right.