I love how the reader view of the new app automatically detects and displays supplemental files in the bar at left. But handling of these files is poor.
When I click on a file, Papers offers a download option and asks me for a save location. Even if I download the file, the software does not automatically attach the file to the paper I'm reading; I have to go back to the library view, locate the downloaded file and attach it manually.
There also does not appear to be any way to open supplemental files from within the reader view; even after downloading and attaching a file, the icons in the side bar (left side of the page in the reader view) still offer the download option. If a file already exists, clicking its icon in the sidebar should open it in a new tab. BTW, opening of supplemental files in their own tabs is great - please keep this.