This is just a minor annoyance, but still annoying. I have dual monitors, and whenever I open a previously saved project, SONAR will actually momentarily open the project in the state which I saved it last, using both monitors (track view in one and multidock in another). However, it then instantly reverts to a default screenset or something and collapses the multidock to the bottom of the main monitor under the track view. How do I prevent it from reverting to this default view and instead use the last state it was in?

Maybe a locked screenset. I can't imagine what else would cause this behaviour.

Mine does this too - so where might this locked screenset switcheroooo be?
 
Edit - Ok found that - but it seems to keep the current screenset from being edited.
To prevent the current screenset from being modified
1.
Make sure the Screenset module is visible in the Control Bar.

2.
Click the Screenset menu and select Lock/Unlock Current Screenset.

A padlock icon appears next to the screenset name in the Screenset menu to indicate that the screenset is locked. To unlock the screenset, select the Lock/Unlock Current Screenset command again.
 
 
 
I wish you could just set up a  screenset and simply save it as the default. I have a basic editing layout that I need to take time to set-up everytime I open a project.

Rbh
I wish you could just set up a  screenset and simply save it as the default. I have a basic editing layout that I need to take time to set-up everytime I open a project.

 
You can. Save the layout anyway you wish in a project template.

Thanks for that Kev999. I guess the issue is with many years of existing projects for me. Having screensets is a great feature - just need take a little time to arrange a set - then import it - to gain a repeatable way to open older projects. Cake does some pretty amazing stuff.
I found this in the docs -
 
Screensets are saved per project, and you can import screensets from other projects. Screensets can be updated, renamed, duplicated and locked to prevent further changes.

I created all my go to screensets then made templates.
To import them is easy enough.
 
Go to the project you have created your screensets in. open it up.
then open a new project you want to import those screensets too.
In that new project go to screensets drop don menu and choose "Import screensets"
Just navigate to the open project where your screensets are and choose import. done.

In your experimentation with the locked screensets does this include the size of the entire Sonar window frame so that it's maximized to both screens?  Sometimes my Sonar somehow gets out of sync when I open it so that I have to drag the corners so that it's maximized on both screens.  I understand that Ableton has a function such that it will maximize the real estate on both screens, I haven't figured this out yet in Sonar.