> I started to use Texniscope instead of preview.app, mainly because it
> refreshes automatically the pdf files, so I don't have to close and
> open again the file to see the changes.
> Is it possible to set texniscope as default pdf viewer within
> lilypond, instead of Preview?
In the Finder, select any one of your PDF's. Then "Get Info" on it,
go to the "Open with..." and change it to TeXniscope, then hit the
"Change All" button.
This will make all your PDF's open in TeXniscope though, not just the
ones from Lilypond.