Thank you for your feedback. I’ve implemented your first suggestion in the latest release. When it comes to the second one I’m skeptical. I do most of my bookmark related stuff in the bookmarks sidebar. Having the errors in the sidebar, I can quickly review them without window switching/rearranging and now I can keep an eye on the progress while opening other tabs - for example to review an error. I consider reducing the font-size of the list though. Displaying bookmarks in the sidebar should be possible on every screen, shouldn’t it? I think I don’t expect too much when I’m expecting people to resize their sidebar. Maybe a misconception ;) Maybe there are even screens where the sidebar can’t get wide enough but how does the bookmark sidebar work on that screens? Well, I will keep that in mind...

I see... thanks again! Actually I was waiting for a replacement for FavIcon Reloader, but at the moment it does not seem to be possible to port its functionality to the new addon-ecosystem. I think that's why the developer could not update it for newer versions of firefox and it is the reason why I came up with this workaround. With 10.000 bookmarks you could always backup/restore your favicons.sqlite, favicons.sqlite-shm and favicons.sqlite-wal files in your profile folder or let this extension run for two hours and turn of the heating instead ;) Maybe, on the other hand side, you can reduce your number of bookmarks by finding many dead links...