If I stretch my whole Sonar view across 2 screens everything works as expected but if I leave Sonar on the main monitor (left) and place the multidock, console or any other screen on the 2nd (right) monitor then any VST3s over the top of that view will only show one plugin at a time.

My details... on the larger monitor, i have no issues, unless i drag something from the smaller to the larger one.
Hanns-G HW191-D 1440x 900
Samsung S27C500 1920 x 1080
Geoforce GTX 750 driver 347.52
Yesterday i had a few issues that i did not document, and after a quick check today the saturation knob plug on the secondary monitor was still an issue... also i could not get a VSTi (oatmeal) to dock in the multidock. Multiple VST3s seem to dock/undock/float as expected on the main monitor, but if i try to open multiple ones on the second monitor w the multidock, they float behind the multidock, but i can move them to the main screen then back over the multidock.

I do also have my second monitor above (have tried all mentioned suggestions, without any change). I will try moving the second monitor to the right, to see if there is any difference. Will report back. 

The saturation knob gui is visible, and tweakable when I move my second monitor to the right(but second monitor is mounted above ). Still have an issue with only one vst in front of the console on my second monitor.

Thanks, I tried that as well and got the same results you have indicated...really weird behavior...

Yes, it is kind of strange. But now that more than one person have tried different "layouts" / solutions and having the same issue, it might be easier to find a solution to this. Lets hope

If doing a virtual re-arranging of the monitors makes it work for you, then what you can do is make the leftmost/topmost monitor be your virtual "main" monitor, and then drag the taskbar over to your "second" monitor. It will mostly work correctly except that when opening new instances of applications, they will probably open on the leftmost/topmost monitor so you will need to drag them to your "main" monitor. It is not ideal but might be better than having some features not work at all.
 
Doing the above will ensure there are no negative coordinates on any of the monitors.
 
Of course this is absolutely still a bug in the software that has this issue and should be fixed.

It's really not much of an issue to me since the saturation knob is simply the amount of acceptable digital distortion you want to load into a track, it is not a module I would ever use, I have much better tools for that...BUT since it is only ONE MODULE that does this (and the vst pin thing) it is a bug that indicates not everything under the hood is clamped down properly...I am not interested in work-arounds but I do appreciate the advice, my issue has always been the code itself not behaving as advertized...
 
I have not gone through the EULA with a fine tooth comb, probably standard boilerplate non-responsibility clauses throughout, chances are multiple monitors with different resolutions in a vertical mode is not something the code team attempted, so the issue is probably a very minor one in the grand scheme of lines of code running ITB...
 
MY only concern has always been that if you cannot grab a Saturation Knob and turn it in the scenario provided are there other issues as well that simply have not been discovered yet?
 
I for one would settle for much less eye candy in trade for complete robust DAW consistency...the issue adds a bit of distortion to an otherwise clean stability program...the fact that more than one user has experienced it gives it credibility.
 
I am sure they are working on it...well no I am not sure of that, I am sure they have been told, and thats enough for me.

I would rather do as I have done so far. I tweak the saturation knob on my main monitor (in the inspector view / Prochannel), and use my console view (on my second monitor) for the rest. I still hope it get resolved, as it is a bit of a hassle to have to use workarounds in an otherwise great DAW.

After updating to Cambridge, I still have the same issues as I had earlier. Both with the Saturation knob, and only one vst showing on the second monitor.