Recently we discovered that the extension provided by Ajar Productions doesn’t work with ePub fixed layout assembled through InDesign book palette, so we advise Justin Putney during our presence at PePCon 2016 in San Diego.
We are very happy to inform you that you can easily solve the problem attacching the .css you find in the location created by Ajar Productions: MacintoshHD:Users:NameUser:Library:ApplicationSupport:Ajar Productions:scrolling frames:scrollingframe_eub.css
Now scrolling frames work perfectly also in an ePub of many different InDesign files assembled by the Book windows. We are very grateful to Ajar Productions for the suggestion to solve the problem! :-)