Hopefully you don't mine me replying to an old post.

I have the same feature request:

I have two projects in one solution. I would like to be able to view them in different windows. However, when I try to open the Projects plug-in in a second window I get the error message "The projects plug-in can be displayed only in one group window."
Or is there a better way to have different groups of files in multiple windows?

thanks,
-shrey