Rated 3 out of 5 stars
It doesn't fully work. I still get "moz-action:switchtab,..." in the urlbar, when I press down to delete the url. And of course the url doesn't actually get deleted, only disappears and its there the next time.This review is for a previous version of the add-on (0.0.2.1-signed.1-signed). This user has a previous review of this add-on.
I'm trying a solution that should make this work more cleanly, including making delete from history work. It is slightly surprising to me that I've managed to do this so easily and I'm almost hesitant to upload it in case I missed something obvious. Anyway, try the newest version.
As for weird things appearing in the urlbar, it shouldn't happen. Not only shouldn't but doesn't, here and in most places. You may have a clash with another addon or some styling that I'm not aware of. Unfortunately I can't fix things I can't reproduce. Try posting more information in the support forum.