In Sonar Professional, my project always opens with the Plug-Ins pane docked on the right, and I need to hit Alt-9 to open the Synth Rack instead and dock it. Every time I open my project I have to go through this. How can I set it up so that the Synth Rack is what I see docked on the right instead of the Plug-In list?

You can create a Project template and set it up the way you like
 
Cj

OK, for new projects that will work. How can I make it so that an existing project will open that way though?

Dock it where you want and lock the screenset.
 
Or set up a Lens.

Bristol_Jonesey
Dock it where you want and lock the screenset.
 
Or set up a Lens.

Or lock the Screenset and don't use the Lens