The new facility to open multiple views of the same source file is darned clever!

Agreed, good job!
No more saving dummy copies of the file.
No more forgetting which is the current version.

** Goes off to buy bigger monitor to display all the panels in

Thanks for the feedback!   The only thing I wasn't overly excited about was that it doesn't indicate that a given tab is a duplicate.  That restriction, however, gets into some of the more complicated design aspects of the tabs themselves.