Two Open Projects?

In all the years I've used Sonar, I've never figured out hot to do this: have two projects open at once. I need to correct a bunch of stuff I mistakenly quantized. Can't figure out any other way but to copy and paste the notes from another copy of the project. I can't undo the quantize because I already closed and reopened the project.

Thanks for that suggestion, Woody. The problem is, this isn't just a track or two. It's an orchestra. not every measure is messed up, but enough are that I need a quick way to replace the bad ones.
When I open another project, BTW, the first one always closes. Not sure what I'm doing wrong.

You can also tile the windows and drag between them. But I usually use the Copy-Ctrl+Tab-Paste method so I can set the Now time precisely, given that un-quantized MIDI doesn't usually start right on the beat.
 
Another option that could save time is to drop the whole source project into the target project, and then shift+drag clips from source to target tracks. I haven't ever had to move enough tracks to make this worthwhile, but it might be the way to go in a big project.