Issue Summary

Clipboard copy paste from Finder supports images. For all other files it uploads them to the page successfully, but doesn't add the thumbnail in the editor.

Steps to Reproduce

1. Open Finder on Macos and copy paste a non image file (pdf/html/image)
2. Edit a page and paste it into the page

Expected Results

File should be uploaded, added as attachment and previewed in the editor as a thumbnail macro

Actual Results

File is uploaded, added as attachment, but not previewed in the editor as a thumbnail macro

Workaround

Add the preview manually from the new attachment