Severe performance degradation in Gnome Shell after upgrade to 20.04 - everything is slow, even moving the mouse through a right-click menu has a severely delayed selection animation.
Video displaying the problem: https://drive.google.com/open?id=1rAKN-ZKks6o9d37hQMbnMgNeAOy8VZyp
ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: gnome-shell 3.36.1-5ubuntu1
ProcVersionSignature: Ubuntu 5.4.0-29.33-generic 5.4.30
Uname: Linux 5.4.0-29-generic x86_64
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Sat May 9 08:57:02 2020
DisplayManager: lightdm
EcryptfsInUse: Yes
InstallationDate: Installed on 2017-02-15 (1178 days ago)
InstallationMedia: Ubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
RelatedPackageVersions: mutter-common 3.36.1-3ubuntu3
SourcePackage: gnome-shell
UpgradeStatus: Upgraded to focal on 2020-05-07 (1 days ago)
The log file is absolutely flooded with errors like:
May 9 08:53:48 volga gnome-shell[3395]: Attempting to call back into JSAPI during the sweeping phase of GC. This is most likely caused by not destroying a Clutter actor or Gtk+ widget with ::destroy signals connected, but can also be caused by using the destroy(), dispose(), or remove() vfuncs. Because it would crash the application, it has been blocked and the JS callback not invoked.
May 9 08:53:48 volga gnome-shell[3395]: The offending signal was notify on MetaDisplay 0x555ad20ba000.
May 9 08:53:48 volga gnome-shell[3395]: Attempting to call back into JSAPI during the sweeping phase of GC. This is most likely caused by not destroying a Clutter actor or Gtk+ widget with ::destroy signals connected, but can also be caused by using the destroy(), dispose(), or remove() vfuncs. Because it would crash the application, it has been blocked and the JS callback not invoked.
May 9 08:53:48 volga gnome-shell[3395]: The offending signal was notify on MetaDisplay 0x555ad20ba000.
May 9 08:53:48 volga gnome-shell[3395]: Attempting to call back into JSAPI during the sweeping phase of GC. This is most likely caused by not destroying a Clutter actor or Gtk+ widget with ::destroy signals connected, but can also be caused by using the destroy(), dispose(), or remove() vfuncs. Because it would crash the application, it has been blocked and the JS callback not invoked.
May 9 08:53:48 volga gnome-shell[3395]: The offending signal was notify on MetaDisplay 0x555ad20ba000.
May 9 08:53:48 volga gnome-shell[3395]: Attempting to call back into JSAPI during the sweeping phase of GC. This is most likely caused by not destroying a Clutter actor or Gtk+ widget with ::destroy signals connected, but can also be caused by using the destroy(), dispose(), or remove() vfuncs. Because it would crash the application, it has been blocked and the JS callback not invoked.
May 9 08:53:48 volga gnome-shell[3395]: The offending signal was notify on MetaDisplay 0x555ad20ba000.