"All Panels Visible" view not showing PDFs

Hello:

I am using EndNote X7.7.1 on Mac.   As of today, when I open a reference, the attached PDFs do not appear in the “All Panels Visible” display option.   When I click on “Preview Panel Not Visible,” the PDF does appears by itself.   Everything was working fine until today. 

Any suggestions for how to get this capability back? 

Thanks!

DJ

Please don’t double post? 

http://community.thomsonreuters.com/t5/EndNote-How-To/quot-All-Panels-Visible-quot-view-not-displaying-PDFs/m-p/147985#M26420