Deleting a horizontal rule from editor doesn't work properly or at all

[JaTochNietDan]

The behaviour around deleting a horizontal rule in the editor doesn't work that well. What I would expect is that when you insert a <hr> tag using insertHTML('<hr>'), you can use backspace to delete the HTML, but this behaviour doesn't really work as expected. The only way I can really seem to get it to delete would be to highlight everything and try and get rid of it that way.