If I checkmark a comment, I can see the checkmark when I re-open the file but my colleague cannot see any when she opens the file on her computer. How do we ‘save’ checkmarks?

I was hoping try67 or Document Geek would add more expertise to Checkmark oddities.  Back in 2011, Document Geek described setting this up to so she could see checkmarks she'd made on one machine when opening the PDF on her laptop via Acrobat's Shared Review.   More recently she wrote on this forum that "checkmarks are user-specific. So I can see if I have checked something off, but you cannot see if I have checked something off."

Curious, I used a text editor to open up an old *.fdf from a PDF on which I knew I had checked comments, and sure enough I found hundreds of "(Marked set by [username])".  For most of these I was the user, but there were a dozen where the user was another person who had added many comments to the file.  Combining this tidbit with Document Geek's insight suggests that my Acrobat X interface may simply not access other users checkmarks.  It looks as though try67's Comments Review Tools adds this ability to Acrobat 2019.

I find checkmarks very useful in my work, and once I make the leap to CC I expect to purchase this try67's package.

David