I have the new Samsung Galaxy Note 9 and when I transferred my files to it I discovered while using the latest update of Adobe Reader that I can no longer edit bookmark name's. After a bit of research I discovered the Adobe app defaulted to full screen mode and while on full screen mode you cannot update bookmarks or change their names. However, if you stop it from going full screen then you are able to rename bookmarks once again and the app behaves as it always did prior. I'm curious as to why this is because I had the Note 8 with an almost identical size screen and I could rename bookmarks at will. I am not sure if it's the new note 9 or the latest update of Adobe Reader that caused the problem but at least now I have a solution. I do hope you can correct this in the future so this app can go full screen once again.