Works as expected in 8.1 Gloucester Splat for me.

Crazy. Does the behavior change if you enable track icons? Or show the Inspector?

Also, do you get the wrong tooltip (or none at all) if you hover over any the mute button?

Bill Jackson [Cakewalk]
Crazy. Does the behavior change if you enable track icons? Or show the Inspector?

No difference either way or combination thereof.
Same behaviour on two completely different systems...

Bill Jackson [Cakewalk]
Also, do you get the wrong tooltip (or none at all) if you hover over any the mute button?

Correct tooltip.

Looks like you're using non-default mouse settings. If so, can you try reproducing with those reset?

Bill Jackson [Cakewalk]
Looks like you're using non-default mouse settings. If so, can you try reproducing with those reset?

No change (the mouse pointers that I was using was a Microsoft extra large system scheme).

After Ctrl+ A to select all tracks and time, clicking on a track number to select or deselect it does nothing...
Frustrating, especially when it's working fine for those who tested...

Pretty sure it's not registering the mouse click in the right location. Though your results of the few tests I asked for don't confirm that. We should schedule a call for tomorrow. I'll send you an email.

Thoughts out of the blue... Probably none of them however..
 
1) When starting a new project make sure it's a blank, i.e. No template.
2) Try a different screenset. Try reverting a screenset.
http://www.cakewalk.com/Documentation?product=SONAR%20X2&language=3&help=WindowManagement.8.html#1204251
 
3) Longshot.. Try deleting your picture cache.
4) Remove any third party mouse software (not drivers).
5) Disable antivirus/malware protection - might have an antikeylogging app.