Issue Summary

When cycling through the attached PDF files on your card in preview mode, the PDF files will no longer be shown, and the user will no longer view them unless they close them and preview them once again. 

This happens when you cycle through the PDFs using your keyboard's arrow keys.

Steps to Reproduce

1. Attach two different PDF files to a card
2. Open one of the attached PDFs to view its preview
3. Go to the next PDF by using the arrow keys on your keyboard
4. You'll notice the preview will be completely blank, and if you return to the previous PDF using the arrow keys, the same behavior will happen. 

Expected Results

Using the arrow keys of your keyboards to cycle through attached PDFs on your card shouldn't affect how they're previewed. 

Actual Results

Using the arrow keys of your keyboards to cycle through attached PDFs causes the PDFs' preview mode to stop working, preventing users from previewing their content. 

Workaround

Users can work around this issue by closing the PDF's preview mode and manually selecting the other PDF they want to preview.