maximising or minimising an HTML5 video sporadically wedges Firefox

[Paul]

When Firefox has been running for a few days, with tens of tabs loaded and has started to run slowly, maximising or minimising a YouTube video can wedge it.

The audio keeps playing until the buffer is exhausted, but everything else is hung: no repainting of the window, no response to keyboard input. CPU usage does not fall to zero, but to around the steady state level it was at before the YouTube page was opened.

ProblemType: Bug
DistroRelease: Ubuntu 17.04
Package: firefox 53.0+build6-0ubuntu0.17.04.1
ProcVersionSignature: Ubuntu 4.10.0-19.21-generic 4.10.8
Uname: Linux 4.10.0-19-generic x86_64
ApportVersion: 2.20.4-0ubuntu4
Architecture: amd64
BuildID: 20170418122848
CurrentDesktop: GNOME
Date: Mon May 1 13:54:57 2017
ExecutablePath: /usr/lib/firefox/firefox
InstallationDate: Installed on 2016-12-02 (149 days ago)
InstallationMedia: Ubuntu-GNOME 16.10 "Yakkety Yak" - Release amd64 (20161012.1)
ProcEnviron:
 LANGUAGE=en_AU:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_AU.UTF-8
 SHELL=/bin/bash
SourcePackage: firefox
UpgradeStatus: No upgrade log present (probably fresh install)

[dino99 (9d9)]

That version is now dead
http://news.softpedia.com/news/ubuntu-17-04-zesty-zapus-has-reached-end-of-life-upgrade-to-ubuntu-17-10-now-519360.shtml