[OS X TeX] TeXShop 4.27: blank Preview window after typesetting

[Murray Eisenberg]

Sometimes now when I typeset a book-length document with TeXShop 4.27 under macOS 10.14.5, the Preview window just shows a dark gray and no content whatsoever! 

But the .pdf itself is OK: I can view in the Mac’s own Preview.app.

What could be wrong?
---
Murray Eisenberg			murrayeisenberg at gmail.com
503 King Farm Blvd #101	Home (240)-246-7240
Rockville, MD 20850-6667	Mobile (413)-427-5334


----------- Please Consult the Following Before Posting -----------
TeX FAQ: http://www.tex.ac.uk/faq
List Reminders and Etiquette: https://sites.esm.psu.edu/~gray/tex/
List Archives: http://dir.gmane.org/gmane.comp.tex.macosx
                https://email.esm.psu.edu/pipermail/macosx-tex/
TeX on Mac OS X Website: http://mactex-wiki.tug.org/
List Info: https://email.esm.psu.edu/mailman/listinfo/macosx-tex