Nice and ... Rated 5 out of 5 stars
It seems opening two or more tabs at the same time (like when Firefox is started) hangs the add-on indefinitely with the msg "Getting DNSSEC status" in the address bar for all the tabs. This also happens with a single tab when Firefox status is changed to offline and then back to online.
Anyways this is definitely a good work with increasing relevance and importance going forward. Thank you for your effort.
Thanks for the bug report, please try DNSSEC Validator 1.1.4 <https://addons.mozilla.org/en-US/firefox/addon/dnssec-validator/versions/1.1.4> released today.