I don't have a solution to your direct question but... I'll offer yet another potential work-around. 🙂
Another option is to use ArcGIS Insights. Its new "Report Builder" feature allows you to create complex and scrolling interactive reports with dozens of maps and charts, etc. I now design most of my demos and presentations in ArcGIS Insights. When I'm done, I just share the interactive workbook with the audience.
Or you can then export the interactive maps, charts, and whatever else from ArcGIS Insights as individual iFrames to embed in Story Maps or any slide-deck software that accepts iFrame (e.g., slides.com).
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Ian Muehlenhaus
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