Thank you for the feedback. I just noticed myself, that Firefox uses Ctrl-B shortcut for the bookmarks sidebar – I have to change that shortcut. I have not planned on supporting tags, but on Firefox that would of course be good feature to have. I'll fix these on next release.

Just published a new version 0.4.2 on 16.6.2021, which have some Firefox fixes and a new shortcut Ctrl-E.