@rafalspuka You tried those steps in a standalone installation or just your regular installation? If in the standalone installation, did you make sure not to enable Opera Sync?
I'm trying to reproduce the issue using the steps you provided, but the folders are remaining.
Try this. In a fresh standalone installation, goto the URL opera://bookmarks, delete all bookmarks and speed dials. Then, empty the bookmark trash. Then, turn on the bookmarks bar and add your bookmarks and folders and bookmarks in the folders. Then, immediately go back to opera://bookmarks and export your bookmarks to an HTML file. Then, upload it somewhere so we can download it and import it.
@leocg Yes, I already understand. To blame. I just wanted to reduce the number of topics created and put it all in one.
As to why these proposals should be implemented. Because it is convenient and I believe that it will be better to use. Especially in the chrome source, the bookmarks bar works exactly as I described. Well, the file size in downloads is a very small thing, a trifle that you also want to see in the interface. All browsers display the size of already downloaded files in the download interface. Even in the same chromium source.