Dec 20 2016
OutlineWidget seems to have been removed, maybe this should be closed?
Dec 19 2016
Unable to reproduce on Firefox 50.
Cannot reproduce. Firefox 50, Elementary OS 0.4, on meta.wikimedia.org (1.29.0). I got this in the HTML:
Able to reproduce on Mediawiki 1.29.0.
Dec 18 2016
Unable to reproduce on Mediawiki 1.29.0.
I can reproduce this issue on Firefox 50.0 on Elementary OS 0.4. I tested on Wikidata (Mediawiki version 1.290).