Post formatting buttons broken on Vivaldi

EbonJaeger

On Vivaldi 2.3.1440.60 (Windows 1809 64-bit), none of the formatting buttons when writing a post do anything when clicked. There are no errors in the dev console. They do work fine in Edge. I'm not sure if this is a Flarum issue or a Vivaldi issue, but I figured I'd post here first.

JoshStrobl

Vivaldi seems to be having issues with constructing CustomElements at this moment in time, because the same issues also apply to Polymer (instead of Mithris, which is what Flarum uses) which ends up breaking Youtube rendering.

See https://forum.vivaldi.net/topic/34730/failed-to-construct-customelement-the-result-must-not-have-attributes