Why can't I see any Prism graphs?

In rare cases, the graphs area of Prism is entirely gray:

We have identified one situation where this comes up: When Prism 6 Mac is configured to use a huge custom paper size (for posters). 

If you encounter this situation, try these alternative fixes, then restart Prism and reload the file. 

• Go to Prism Preferences, File&Printer tab, and uncheck the checkbox "Do not save (or read) page size to (or from) .pzf file".
• In Prism, drop the File menu, and choose Page Setup. Choose a different page size or printer. 
• Go to the System Preferences, Printer and fax pane, and change the default printer and/or default paper size.